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Single Molecule Workshop

29th International Workshop on “Single Molecule Spectroscopy and Super-resolution Microscopy”

October 8 - 10, 2024, Berlin, Germany

Image Single Molecule Workshop

Meet the single molecule community in Berlin!

The 29th edition of the Single Molecule Workshop will take place from Ocotober 8 – 10, 2024. We are looking forward to welcoming you in Berlin. Join us for an exciting and stimulating conference by either giving a talk, presenting a poster or even without any presentation. As always, we will be awarding a “Best Student Talk” prize worth 750 Euro.

Audience during an oral presentation


Aim and purpose

The focus of PicoQuant’s long-standing workshop lies on ultrasensitive optical detection down to the single molecule level as well as beyond the classical diffraction limit. The event provides an interdisciplinary platform for exchanging ideas and recent results between researchers and professionals working in the fields of physics, chemistry, biology, life and materials science.

During the workshop, talks and posters are presented that cover a wide range of applications and methods revolving around the challenging field of Single Molecule Spectroscopy.

Covered topics include:

  • Fluorescence Lifetime Imaging (FLIM)
  • Single molecule Förster Resonance Energy Transfer (smFRET)
  • Polarization and Anisotropy based techniques
  • Quantitative imaging methods
  • New fluorescence sensors and labeling schemes
  • Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Lifetime Correlation Spectroscopy (FLCS)
  • Stimulated Emission Depletion (STED) microscopy
  • Single Molecule Localization Microscopy (e.g., PALM, STORM, dSTORM, GSDIM, PAINT)
  • Open source data analysis solutions
  • Big Data and Machine Learning approaches to superresolution and single molecule techniques

Both widefield and confocal fluorescence microscopy techniques are covered as well as in vivo and in vitro measurements with single molecule sensitivity.

Important dates

  • Deadline for abstract submission TALKS: September 6, 2024
  • Deadline for abstract submission POSTERS: September 20, 2024
  • Deadline for fee waiver application: June 28, 2024
  • Final deadline for workshop registration: September 20, 2024
  • Notification on acceptance of abstracts: September 2024
  • Program available: September 2024

Student Award

Icon Student AwardAs nurturing young scientists is important to PicoQuant, we host a competition for the “Best Student Talk” with an award worth 750 Euro. Undergraduate and graduate students are invited to submit their contributions until September 6, 2024. Please indicate during abstract submission if you wish to participate in the contest (abstract submission will be open soon).


Contact

Workshop coordinator: Claudia Bergemann

Tel: +49-30-1208820-87
Fax: +49-30-1208820-90
Email: workshop@picoquant.com

Poster session at the 18th workshop

Invited speakers and preliminary presentation titles

  • Suzanne BlumSuzanne A. Blum
    University of California, Irvine USA
    "Chemical Reaction Insights through FLIM"
  •  
  • Anindya DattaAnindya Datta
    IIT Bombay, India
    "Elucidation of exciton dynamics in semiconductor nanocrystals using Fluorescence Lifetime Correlation Spectroscopy"
  •  
  • Lars HubatschLars Hubatsch
    Max Planck Institute of Molecular Cell Biology and Genetics, Germany
    "Transport across phase boundaries"
  •  
  • Emmanuel MargeatEmmanuel Margeat
    Centre de Biologie Structurale, Montpellier, France
    "Dissecting the structural dynamics of a GPCR using smFRET"
  •  
  • Sergio Padilla-ParraSergio Padilla-Parra
    King’s College London, United Kingdom
    "Employing multiparameter spectral imaging to HIV-1 entry"
  •  
  • Susana RochaSusana Rocha
    Katholieke Universiteit Leuven, Belgium
    "Imaging Cellular Forces: From Micro to the Nano Scale"
  •  
  • Quan WangQuan Wang
    National Institutes of Health, USA
    "High-precision single-molecule spectroscopy and charge sensing with an anti-Brownian trap"
  •  
  • Stefanie Weidtkamp-PetersStefanie Weidtkamp-Peters
    Heinrich-Heine University Duesseldorf, Germany
    "Studying interaction in biological samples by applying spectroscopic methods"
  •  

Program (as of September 17)

13.30 - 13.45Rainer Erdmann, Berlin, Germany
Opening Remarks
FLIM SessionQuan Wang
13.45 - 14.15
Lars Hubatsch, Dresden, Germany (Invited Talk)

Capturing Molecular Transport across Phase Boundaries by Fluorescence Microscopy

Lars Hubatsch

Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

Cells compartmentalize biochemical processes within organelles. Compartmentalisation can be achieved by selectively admitting biomolecules, either through a membrane or, in the case of biomolecular condensates, via the condensate-bulk interface. While membrane transport is well-studied, the mechanisms regulating transport across condensate interfaces remain unclear, hindering our understanding of dynamic condensate functions—a key focus in our lab. To address this, we employ various optical techniques, combined with data analysis and theory. I will present an example of this interdisciplinary approach, demonstrating how quantitative live microscopy, coupled with mean-field and single-molecule theory, reveals insights into molecular transport across phase boundaries. Our findings show that in binary mixtures, the condensate interface is near local equilibrium, allowing molecules to enter and exit without delay. However, theory predicts complex behavior in multi-component mixtures. I will explore these cases, their experimental predictions, and their intracellular functional implications.

14.15 - 14.35
Gabriel Moya, Munich, Germany (Student Award)

Single-molecule spectroscopy & super-resolution microscopy at the biochemistry lab bench.

Gabriel Moya1,2, Oliver Brix1, Philipp Klocke1, Paul Harris3, Nicolas Wendler1,2, Jorge Luna1, Eitan Lerner3,4, Niels Zijlstra1, Thorben Cordes1,2

1Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians Universität München, Planegg-Martinsried, Germany
2Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Technische Universität, Dortmund, Dortmund, Germany
3Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics Science, The Edmond J. Safra Campus, The Hebrew University of, Jerusalem, Jerusalem, Israel
4The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel

Over the past decades, single-molecule and super-resolution microscopy have advanced and become essential tools for life science research. However, there is a growing gap between the state-of-the-art and what is accessible to biologists, biochemists, medical researchers, or labs with financial constraints1,2,3. To bridge this gap, we introduce Brick-MIC, a versatile and affordable 3D-printed micro-spectroscopy and imaging platform. Brick-MIC enables the integration of various fluorescence imaging techniques with single-molecule resolution within a single platform and allows for quick switching between different modalities. We present variants of Brick-MIC that support single-molecule fluorescence detection4, fluorescence correlation spectroscopy5, and super-resolution imaging (STORM6 and PAINT7). We foresee that this affordable, flexible platform will be a valuable tool for many laboratories worldwide.


[1] G. Marqués, T. Pengo, M. A. Sanders, eLife 9, e55133 (2020)

[2]  R. M. Power, J. Huisken, Nat Methods 16, 1069–1073 (2019)

[3] J. Hohlbein, B. Diederich, B. Marsikova, E. G. Reynaud, S. Holden, W. Jahr, R. Haase, K. Prakash, Nat Methods 19, 1020–1025 (2022).

[4] J. Hohlbein, T. D. Craggs, T. Cordes. Chem. Soc. Rev. 43, 1156–1171 (2014).

[5] L. Yu, Y. Lei, Y. Ma, M. Liu, J. Zheng, D. Dan, P. Gao, Frontiers in Physics 9 (2021).

[6] M. J. Rust, M. Bates, X. Zhuang,  Nat Methods 3, 793–796 (2006).

[7] R. Jungmann, C. Steinhauer, M. Scheible, A. Kuzyk, P. Tinnefeld, F. C. Simmel, Nano Lett. 10, 4756–4761 (2010).

14.35 - 14.55
Chenyuan Yan, München, Germany (Student Award)

Exploring the Interactions between DNA and Graphene via Graphene Energy Transfer (GET)

Chenyuan Yan1, Alan M. Szalai1, Lars Richter1, Giovanni Ferrari1, Jakob Hartmann1, Merve-Zeynep Kesici1, Bosong Ji1, Andrés M. Vera1, Philip Tinnefeld1, Izabela Kamińska1,2

1Department of Chemistry and Center for NanoScience, Ludwig Maximilian University of Munich, Butenandtstr. 11, 81377 Munich, Germany
2Institute of Physical Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland

Graphene is well known as an efficient fluorescence quencher, and has been well-studied as a broadband and unbleachable energy acceptor.[1,2] The energy transfer efficiency from an emitter to graphene scales with d-4, where d is a distance between both, and the characteristic d0 = 18 nm represents the distance with the 50% Graphene Energy Transfer (GET) efficiency.[1,2] Taking advantage of the GET, the height of the single dye molecule on graphene can be sensitively determined from the fluorescence intensity and lifetime measurements.[2,3] In our previous work, we successfully utilized DNA origami as nanopositioners to precisely control the height of dye molecules on graphene.[2,3] More recently, we developed a new ssDNA-dsDNA-graphene system, where the dsDNA segment stands vertical on graphene.[4] We use this system to visualize structural properties of DNA or to further visualize the direct interactions between DNA with protein.[4] In this work, we study the interactions between ssDNA/dsDNA with graphene to better understand how long the ssDNA anchor is needed to immobilize the construct on graphene, and what happens if the length of ssDNA anchor is shortened in order to get more information about the interaction mechanism between DNA and graphene.


References: [1] Gaudreau, L. et al., Nano Lett. 13, 2030 (2013). [2] Kamińska, I. et al., Nano Lett. 19, 4257 (2019). [3] Kamińska, I. et al., Adv. Mat. 33, 2101099 (2021). [4] Szalai, A. M. et al., bioRxiv. /doi.org/10.1101/2023.11.21.567962.

14.55 - 15.15
Sigrid Milles, Berlin, Germany

Intrinsically disordered regulators of endocytosis - an integrated NMR/single molecule fluorescence approach

Sigrid Milles

FMP Berlin, Robert-Roessle-Str. 10, 13125 Berlin, Germany

Intrinsically disordered proteins (IDPs) lack clearly defined structure and are therefore highly flexible and easily adaptable to different binding partners. This makes them important players in many biological processes, often with vital regulatory functions. Their dynamic features and broad range of interaction modes, however, render them difficult to study and analyzing their complexes often requires integrated approaches. Integrating complementary parameters from of nuclear magnetic resonance (NMR) and single molecule fluorescence approaches allowed us to describe the conformational landscape of IDPs at molecular resolution and promises to shed new light onto various biological processes.

Among those counts clathrin mediated endocytosis. The early phases of clathrin mediated endocytosis are organized through a highly complex interaction network mediated by clathrin associated sorting proteins (CLASPs) that comprise long intrinsically disordered regions (IDRs). We characterize the IDRs of those CLASPs in their entirety and at molecular resolution, uncovering a plethora of interactions of various strengths and dynamic features with their endocytic interaction partners, proposing a rationale for how first interactions and dynamic rearrangement of partners take place during the uptake of a coated vesicle.


Quantitative Description of Intrinsically Disordered Proteins Using Single-Molecule FRET, NMR, and SAXS.
Naudi-Fabra S, Tengo M, Jensen MR, Blackledge M, Milles S.
J Am Chem Soc. 2021 Dec 8;143(48):20109-20121.

An extended interaction site determines binding between AP180 and AP2 in clathrin mediated endocytosis.
Naudi-Fabra S, Elena-Real CA, Vedel IM, Tengo M, Motzny K, Jiang PL, Schmieder P, Liu F, Milles S.
Nat Commun. 2024 Jul 13;15(1):5884.

15.15 - 15.50COFFEE BREAK & EXHIBITION
FRET I SessionLars Hubatsch
15.50 - 16.20
Quan Wang, Bethesda, United States (Invited Talk)

High-precision single-molecule spectroscopy and charge sensing with an anti-Brownian trap

Quan Wang

National Institutes of Health, NIDDK, Bethesda, USA

By counteracting random diffusion in aqueous solution, the Anti-Brownian Electrokinetic (ABEL) trap has evolved to be a versatile and powerful platform for single-molecule spectroscopy and sensing. I describe two recently developed modalities, each of which enables new capabilities for single-molecule biophysics. First, ABEL-FRET achieves ultrahigh, shot-noise limited resolution of smFRET efficiency in solution without surface tethering. Second, we demonstrate real-time monitoring of single-molecule phosphorylation cycles by direct sensing of the charge state of individual molecules in solution.

16.20 - 16.40
Thorben Cordes, Dortmund, Germany

Dissecting Mechanisms of Ligand Binding and Conformational Changes in Substrate Binding Proteins

Thorben Cordes

Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany

Ligand binding and conformational changes of biomacromolecules play a central role in the regulation of cellular processes. It is important to understand how both are coupled and what their role is in biological function. The biochemical properties, conformational states, and structural dynamics of periplasmic substrate-binding proteins (abbreviated SBPs or PBPs), which are associated with a wide range of membrane proteins, have been extensively studied over the past decades. Their ligand-binding mechanism, i.e., the temporal order of ligand-protein interactions and conformational changes, however, remains a subject of controversial discussion. I here summarize our past and ongoing efforts to clarify how ligand binding and conformational changes are coupled in SBPs using a variety of different biophysical techniques including single-molecule FRET.


https://www.nature.com/articles/nsmb.2929

https://elifesciences.org/articles/44652

https://www.pnas.org/doi/abs/10.1073/pnas.2026165118

https://www.biorxiv.org/content/10.1101/2023.08.02.551720v1.abstract

16.40 - 17.00
Kseniia Volkova, Berlin, Germany (Student Award)

Confocal microscopy in a controlled atmosphere for nano-scale nuclear magnetic resonance spectroscopy

Kseniia Volkova1, Abhijeet Kumar2, Karolina Schüle3, Jens Fuhrmann3, Fedor Jelezko3, Kirill Bolotin2, Boris Naydenov1

1Department Spins in Energy Conversion and Quantum Information Science (ASPIN), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekuléstraße, Berlin, Germany
2Department of Physics, Freie Universität Berlin, Arnimallee, Berlin, Germany
3Institut für Quantenoptik, Freie Universität Ulm, Albert-Einstein-Allee, Ulm, Germany

Different studies performed on nitrogen-vacancy (NV) centers in diamond proved them to be efficient quantum sensors of materials deposited on a diamond surface. The properties of the NV centers can be used for detecting nanoscale magnetic fields, allowing nuclear magnetic resonance (NMR) spectroscopy on samples at the level of a single molecule [1] or for sensing single nuclear spins [2]. Among the materials studied or proposed for NV center-based NMR spectroscopy, many are sensitive to oxygen or humidity and can alter their properties upon air exposure. One such material is black phosphorus. Phosphorus isotope 31P is a good candidate for the NV center-based spin detection thanks to its 100% natural abundance and a high gyromagnetic ratio (γ = 1.725 kHz/G). Transferring a thin black phosphorus flake on a diamond with NV centers implanted a few nanometers below the surface could be one of the approaches to fabricate the hardware of a quantum simulator [3].  The main disadvantage of black phosphorus is that it degrades under ambient conditions. Therefore, we present a confocal microscope with a glovebox enclosure for performing NV-based NMR spectroscopy on multi-layered black phosphorus.


[1] I. Lovchinsky, A. O. Sushkov, E. Urbach, N. P. de Leon, S. Choi, K. De Greve, R. Evans, R. Gertner, E. Bersin, C. Müller, L. McGuinness, F. Jelezko, R. L. Walsworth, H. Park and M. D. Lukin, Science, 351, 836-841 (2016).

[2] C. Müller, X. Kong, J. M. Cai, K. Melentijević, A. Stacey, M. Markham, D. Twitchen, J. Isoya, S. Pezzagna, J. Meijer, J. F. Du, M. B. Plenio, B. Naydenov, L. P. McGuinness and F. Jelezko, Nature communications, 5, 4703 (2014).

[3] J. Cai, A. Retzker, F. Jelezko and M.B. Plenio, Nature Physics, 9, 168-173 (2013).

17.00 - 17.20
Noah Salama, Düsseldorf, Germany (Student Award)

Performing and Analyzing FRET Nanoscopy Measurements on DNA-Origami Platforms with sub-Nanometer Precision

Noah Salama1, Jan-Hendrik Budde1, Nicolaas van der Voort1, Suren Felekyan1, Julian Folz1, Ralf Kühnemuth1, Paul Lauterjung1,2, Michelle Rademacher1,3, Markus Köhler4, Andreas Schönle4, Julian Sindram5, Marius Otten5, Anders Barth1,6, Christian Herrmann2, Matthias Karg5, Claus A. M. Seidel1

1Chair for Molecular Physical Chemistry, Heinrich-Heine-Universität Düsseldorf, Germany
2Physical Chemistry I, Ruhr-Universität Bochum, Germany
3Institute for Physical Chemistry II, Heinrich-Heine-Universität Düsseldorf, Germany
4Abberior Instruments GmbH, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany
5Lehrstuhl für Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
6Department of Bionanoscience, Delft University of Technology, Delft, Netherlands

Super-resolution microscopies provide an invaluable tool for studies of larger cellular structures and molecular assemblies with nanometer precision, while being minimally invasive and highly selective to the molecule of interest. However, the currently achieved spatiotemporal resolution cannot resolve distances on the size of individual molecules, thus conformational fine structure and dynamics on the scale of single molecules remain concealed.

We overcome this resolution limit through the combination of multiparameter FRET-spectroscopy and colocalization stimulated emission depletion (cSTED) microscopy, giving a versatile and readily available tool for investigation of structure and dynamics on a single-molecule level, with Ångström precision.[1]

The analysis of FRET parameters yields the Euclidean distance while colocalization provides the distance projected onto the image plane. Consequently, the combined information allows for the determination of 3D-orientations via Pythagoras' theorem. We established an easy-to-follow workflow for performing and analyzing FRET nanoscopy measurements and obtain inter-dye distances with sub-nanometer precision.

We demonstrate the feasibility and accuracy of our approach by using standardized DNA origami platforms with two dye pairs as a benchmark sample. We simultaneously localize donor and acceptor dyes of single FRET pairs with nanometer resolution and quantitatively measure intramolecular distances with sub-nanometer precision over a large dynamic range.


[1] Budde, J.-H. et al., arXiv preprint (2022)

17.20 - 18.50POSTER SESSION 1 & GET TOGETHER
F-Techiques SessionSusana Rocha
09.00 - 09.35
Stefanie Weidtkamp-Peters, Duesseldorf, Germany (Invited Talk)

Studying interaction in biological samples by applying spectroscopic methods

Stefanie Weidtkamp-Peters

Heinrich-Heine University Duesseldorf, Germany

A main goal of molecular cell biology is to identify and monitor the interacting network of proteins and other molecules in a cell with respect to different positions and conditions to understand the biological processes on a molecular level. The investigation of protein interactions in living plant tissue has become of increasing importance in recent years. A high spatial and temporal resolution for the observation of in vivo protein interaction is needed, e.g., in order to follow changes of interactions and complex formation over time. In vivo Fluorescence or Förster resonance energy transfer (FRET) measurements allows for detailed analyses of interacting molecules in their natural environment at a subcellular level. Especially FRET-FLIM (Fluorescence lifetime imaging microscopy) measurements provide an extremely powerful and reliable tool meeting the demands for investigating in vivo protein interaction also quantitatively and with high precision. On the other hand, the most commonly used fluorescent reporters used in this context, the fluorescent proteins, show a weak quantum yield and a complex decay behavior and are affected by changing environmental conditions, like changes in the pH. In addition strong autofluorescence of the tissue under investigation can significantly contribute to the acquired signal, which makes the analysis of the recorded data difficult or only allows insufficient quantitative analysis. In my talk I will show examples of interaction studies in plant tissue and ideas on how to overcome the limitations imposed by the measurement conditions to obtain quantitative results to help understand the network of interacting proteins in plant tissues.


Maika, J.E., Kramer, B., Strotmann, V.I., Wellmer, F., Weidtkamp-Peters, S., Stahl, Y., and Simon, R. (2023). One pattern analysis (OPA) for the quantitative determination of protein interactions in plant cells. Plant Methods 19, 73. 10.1186/s13007-023-01049-3. Burkart, R.C., Strotmann, V.I., Kirschner, G.K., Akinci, A., Czempik, L., Dolata, A., Maizel, A., Weidtkamp-Peters, S., and Stahl, Y. (2022). PLETHORA-WOX5 interaction and subnuclear localization control Arabidopsis root stem cell maintenance. Embo Rep 23, e54105. 10.15252/embr.202154105. Stahl, Y., Grabowski, S., Bleckmann, A., Kuhnemuth, R., Weidtkamp-Peters, S., Pinto, K.G., Kirschner, G.K., Schmid, J.B., Wink, R.H., Hulsewede, A., et al. (2013). Moderation of Arabidopsis root stemness by CLAVATA1 and ARABIDOPSIS CRINKLY4 receptor kinase complexes. Curr Biol 23, 362-371. 10.1016/j.cub.2013.01.045.

09.35 - 09.55
Or Eivgi, Heidelberg, Germany

Subtle Polymer Dynamics Revealed by Fluorescence Lifetime Imaging Microscopy

Or Eivgi, Suzanne A. Blum

Department of Chemistry, University of California, Irvine, Irvine California, 92697-2025 United States

In this work, Fluorescence lifetime imaging microscopy (FLIM) is developed to investigate the dynamics of ring-opening-metathesis-polymerization-(ROMP-) based polymers. By designing  ROMP functionalized viscosity-sensitive fluorescent molecular rotors that change their fluorescence lifetime based on the viscosity of their polymeric microenvironment, simultaneous imaging of changing physical parameters and catalytic activity in living polymers was achieved.1 In this system, coupling FLIM with intensity fluorescence microscopy enabled correlation of the decreasing catalytic activity of Grubbs catalysts inside of polydicyclopentadiene particles with increasing microenvironment viscosity. Moreover, it was demonstrated that microenvironment viscosity changes during polymerization are monomer-dependent, accelerated by crosslinking, and variable in the rate of change between different particles and subparticle regions of the same sample. Together, these data provide a physical mechanism for irregular reaction kinetics observed for single Grubbs catalysts. The sensitivity of the viscosity-sensitive rotors also uncovered and quantitatively elucidated undisclosed differential block-selective responses toward solvation changes upon addition of DMSO and THF to self-assembled ROMP-based amphiphilic block copolymers.2 The sensitivity of this method provided unique information on block-selective solvent-triggered assembly and disassembly mechanisms, revealing behaviors invisible to or with superior sensitivity to traditional 1H-NMR spectroscopy. This block-selective information can be further used to fine tune block copolymer assembly and disassembly.


(1) Eivgi, O.; Blum S. A.  J. Am. Chem. Soc. , 144, 13574–13585 (2022)

(2) Eivgi, O.; Ravenscroft, A. C.; Blum, S. A.,  J. Am. Chem. Soc. , 145, 2058–2063 (2023)

09.55 - 10.15
Koushik Sreenivasa, Delft, Netherlands (Student Award)

Measuring the sequence dependence of DNA looping at high-throughput using single-molecule FRET

Koushik Sreenivasa, Chirlmin Joo

Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

DNA bending/flexibility is shown to be a characteristic in many processes within a cell such as gene regulation and DNA repair. Despite its' importance it is not yet completely understood on a molecular scale how the sequence of DNA controls the bending propensity. One of the limitations is the lack of high-resolution, high-throughput technique(s) for analyzing the large breadth of sequence space. Using a new high-throughput, single-molecule fluorescence method labelled SPARXS, we characterise the kinetics of DNA looping of many different sequences in a single-experiment. With conventional technique, we find that differing the sequences by few nucleotides is enough to change the rates of looping and unlooping. We aim to use SPARXS to get a more complete picture of how sequence dictates DNA looping kinetics and thereby setup foundation for further experiments.

10.15 - 10.35
Abhilash Kulkarni, Stockholm, Sweden (Student Award)

Multiplexed NIR FCCS using a single superconducting nanowire single photon detector

10.35 - 10.45GROUP PICTURE
10.45 - 11.20COFFEE BREAK & EXHIBITION
Super Resolution Microscopy I SessionStefanie Weidtkamp-Peters
11.20 - 11.50
Sergio Padilla-Parra, London, United Kingdom (Invited Talk)

Visualizing the coupling between Gag proteolysis and Env clustering in native HIV-1 viruses

Sergio Padilla-Parra

King’s College London, United Kingdom

Envelope glycoprotein (Env) trimers in HIV-1 serve as molecular machines for viral entry into host cells, including CD4+ T cells and macrophages. Recent advancements in super resolution light microscopy techniques have shed light on the previously unseen organization of Env on the surface of mature HIV-1 virions, revealing distinct protein clusters rather than random distribution. These Env clusters are not only central to viral entry mechanisms but also serve as critical targets for both innate and adaptive immune responses. Despite significant progress in elucidating the structural aspects of Env a crucial gap remains in understanding the collective behavior of multiple units and their impact on viral entry and fusion processes. Notably, a tight coupling between Env clustering and Gag proteolysis, wherein proteolytic processing of the Gag polyprotein by the viral protease facilitates the transition from immature to mature, infectious virions, has been observed. However, the precise timing and kinetics of Gag processing and its relationship with Env clustering dynamics are not fully understood. To address this gap, we introduce a novel approach involving the tagging of the variable region 4 (V4) loop of Env with a synthetic tag called ALFAtag. This innovative tagging strategy, guided by AlphaFold predictions, enables specific labeling using anti-ALFA single-domain antibodies (sdAbs), thus allowing for the study of Env clustering within native viruses while preserving the native Env structure. Due to the small size of both the ALFA-tag and sdAbs, the ALFA system results in minimal linkage error and it is perfectly suitable to ultra-resolved Env clustering via a single-molecule based super-resolution fluorescence microscopy, known as DNA-PAINT. Furthermore, by labeling the Gag polyprotein with mTurquoise2 internally and employing a dark fluorogen (FAST) for Förster resonance energy transfer (FRET), we can monitor proteolytic release of the fluorophore from Gag, which correlates with an increase in fluorescence lifetime due to FRET disruption. Ultimately, this strategy enables us to discern the degree of virus maturation with high precision and dynamic range whilst visualizing Env clustering, offering a detailed depiction of how Env organises before and during virus maturation. Cryo-electron Tomography (CryoET) shows that the maturation biosensors preserve capsid structure in mature viruses. Additionally, we validate and cross-compare our findings using Ångström resolution localization microscopy (RESI) adapted for native viruses, further enhancing the robustness of our observations. Our results highlight the dynamic clustering and cooperative behavior of individual Envs and how they affect intramolecular dynamics as critical determinants of efficient viral cell entry.

11.50 - 12.10
Christian Eggeling, Jena, Germany

Pitfalls and workarounds of photoblueing effects in advanced fluorescence microscopy

Christian Eggeling

Leibniz Institute of Photonic Technology, Jena, Germany
Institute for Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany

Photobleaching is a major limitation in fluorescence microscopy. A special photobleaching pathway is photoblueing, i.e. the conversion of fluorescent molecules into species of blue-shifted emission properties. We investigated details of this photoblueing effect for confocal and STED microscopy as well as for spectral imaging of environment sensitive membrane dyes and outline induced artefacts as well as strategies to avoid these.

12.10 - 12.30
Tao Chen, Göttingen, Germany

Super-resolved axial imaging of piconewton cellular traction forces with metal-induced energy transfer spectroscopy/imaging

Dong-xia Wang, Jörg Enderlein, Tao Chen

Third Institute of Physics – Biophysics, Georg August University, Friedrich-Hund-Platz 1, Göttingen, 37077, Germany

Cell mechanics play a pivotal role in regulating numerous vital biological processes. To better understand how mechanical forces are coupled to biochemical signaling pathways, methods are needed to map the nanoscale distribution of forces in living cells. Molecular tension probes (MTPs) have been developed to map the magnitude of receptor force with pN sensitivity.1,2 This enables various fluorescence microscopes to map receptor forces for different cellular adhesion structures. However, current fluorescence techniques can only map force along the lateral dimension with a resolution of tens of nanometers and the axial dimension with a resolution of 50-60 nm.

Here, we utilized metal-induced energy transfer (MIET) spectroscopy/imaging3 with a widely recognized DNA-based hairpin MTP (MIET-MTP, see Figure) to map the cell force along the axial dimension with a nanometer-level resolution. MIET not only reports the height change in MTP but also presents the corresponding height profile of plasma membrane (PM), revealing a positive and negative correlation between the MTP and PM for focal adhesions and podosomes, respectively. Moreover, MIET-MTP exhibits remarkable versatility, including its potential integration with DNA-PAINT to facilitate 3D force mapping at nanometer precision. MIET-MTP will serve as a potent tool, bridging the gap between structural biology and mechanobiology.


[1] Zhang, Y., Ge, C., Zhu, C. et al. DNA-based digital tension probes reveal integrin forces during early cell adhesion. Nat Commun 5, 5167 (2014).

[2] Schlichthaerle, T., Lindner, C. & Jungmann, R. Super-resolved visualization of single DNA-based tension sensors in cell adhesion. Nat Commun 12, 2510 (2021).

[3] Chizhik, A., Rother, J., Gregor, I. et al. Metal-induced energy transfer for live cell nanoscopy. Nature Photon 8, 124–127 (2014).

12.30 - 12.50
Dominic A. Helmerich, Würzburg, Germany

Beyond Resolution Limits: Sub-10nm Insights via Photoswitching Fingerprint analysis

Dominic A. Helmerich1, Danush Taban1, Mara Meub1, Marcel Streit2, Alexander Kuhlemann1, Sören Doose1, Gerti Beliu2, Markus Sauer1,2

1Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
2Rudolf Virchow Center, Research Center for Integrative and Translational Bioimaging, University of Würzburg, 97080, Würzburg, Germany

The field of super-resolution microscopy has revolutionized biological imaging by providing direct insights into cellular structures and protein arrangements. Spatial resolution in the single-digit nanometer range can be achieved, matching the size of cellular molecules. Recent high-resolution microscopy methods have demonstrated localization accuracies in the angstrom range and spatial resolution in the lower single-digit nanometer range for reference structures. However, achieving this spatial resolution in biological samples remains challenging due to critical parameters that must be met, posing a significant hurdle to attaining molecular resolution. In this work, we demonstrate how to leverage this challenge to our advantage. We present a widely accessible method to extract information well below the lateral resolution using simple microscopy techniques. This approach can reveal insights into biological systems and processes that would typically remain hidden and is applicable to a broad range of subjects, including living systems.


Helmerich, D.A., Beliu, G., Taban, D. et al., Nat Methods, 19, 986–994 (2022)

12.50 - 13.10
Roman Tsukanov, Göttingen, Germany

A versatile microfluidics platform for enhanced multi-target super-resolution microscop

Roman Tsukanov1, Samrat Basak1, Nikolaos Mougios2, Nazar Oleksiievets3, Felipe Opazo2,4,5, Jörg Enderlein1,6

1III. Institute of Physics – Biophysics, Georg August University, 37077 Göttingen, Germany.
2Institute of Neuro-and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany.
3Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden.
4Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany.
5NanoTag Biotechnologies GmbH, 37079 Göttingen, Germany.
6Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), Georg August University, 37077 Göttingen, Germany.

Super-resolution microscopy (SRM) [1] has become a standard tool for biomedical imaging, capable of revealing structural information with unprecedented detail. However, achieving localization precision on the nanometer scale requires advanced SRM technologies and optimized sample performance. To achieve this, the most suitable fluorophores for the specific type of microscopy must be selected. Furthermore, the photophysical performance of a fluorophore must be optimized through tight control of the fluorophore environment, achieved by manual injection of an imaging buffer or by using a versatile microfluidics system.

Here, we develop an Air-PREssure-based MIcroFluidics System (APREMIFS) and demonstrate its implementation for multiplexed super-resolution imaging. We used APREMIFS to perform the sequential imaging of cellular targets (cytoskeleton and focal adhesion proteins) via Exchange-PAINT [2], achieving an average localization precision of 10 nm for all imaged targets. Furthermore, we utilized gold nanoparticles as fiducial markers to correct for mechanical drift and to precisely align and overlay images of different targets. APREMIFS is a highly versatile system that can be adjusted for multiple experimental scenarios and combined with different types of microscopes. We anticipate that APREMIFS will significantly enhance multiplexed super-resolution imaging and enable full automation of complex multiplexed SRM imaging protocols.


[1] Koenderink, AF; Tsukanov, R; Enderlein, J; Izeddin, I.; Krachmalnicoff. V., Nanophotonics, 11 (2), 169-202 (2022).

[2] Sograte-Idrissi, S.; Oleksiievets, N.; Isbaner, S.; Eggert-Martinez, M.; Enderlein, J.; Tsukanov, R.*; Opazo, F.*, Cells, 8 (1), 48 (2019).

13.10 - 14.40LUNCH BREAK
Super Resolution Microscopy II SessionSergio Padilla-Parra
14.40 - 15.10
Susana Rocha, Leuven, Belgium (Invited Talk)

Imaging Cellular Forces: From Micro to the Nano Scale

Susana Rocha

Katholieke Universiteit Leuven, Belgium

Understanding the complex interplay between cells and their surrounding matrix is paramount for advancing biomimetic scaffold design. By pushing and pulling on the extracellular matrix (ECM), cells continuously sense the dynamic mechanical cues from their environment and generate mechanical feedback. Mechanical characterization of the matrix surrounding the cells has shown that contractile cells can generate a stiffness gradient in biological gels. Such cell-generated forces can reorganize and deform the natural ECM fibers, causing fiber densification and alignment. Traditional characterization methods like electron microscopy and scanning probe microscopy provide high spatial resolution but fall short in capturing these dynamic processes in situ. This talk highlights the use of fluorescence microscopy to characterize the structure of synthetic hydrogels and quantify the traction forces generated by the cells. We use confocal imaging and bead-free traction force microscopy (TFM) to demonstrate how a fully synthetic biomimetic hydrogel can be used as a platform for exploring the influence of biochemical and mechanical factors on cell-matrix interactions.. This biomimetic hydrogel, formed from oligo(ethyleneglycol)-functionalized polyisocyanate (PIC) polymers, is formed by non-covalent interactions and exhibits a nonlinear mechanical response at low stresses. We further investigate the forces that cells apply at a molecular scale using FRET-based tension sensors. These sensors allow us to measure the molecular-scale forces exerted by the cells, providing insights into how cells interact with and remodel their microenvironment. Our fluorescence microscopy-based approach sheds light on how physical cues regulate cell-matrix interactions, offering insights for the rational design of biomimetic materials.

15.10 - 15.30
Moritz Burmeister, Aarhus, Denmark (Student Award)

Extracting Rate Constants Using Single Molecule Localization Microscopy

Moritz Burmeister1, Rebecca Torp Rosendal1, Richard Kosinski2, Barbara Saccà2, Victoria Birkedal1

1Interdisciplinary Nanoscience Center (iNANO) & Department of Chemistry, Aarhus University, Denmark
2Center of Medical Biotechnology (ZMB), Faculty of Biology, University of Duisburg-Essen, Germany

Understanding the fundamental principles of biomolecular interactions is crucial for advancements in diagnostics and drug development. Single molecule techniques provide key insights into these interactions by looking beyond ensemble averages and giving access to potentially heterogenous population distributions.
We employ single molecule localization microscopy to investigate dynamic binding interactions between biomolecules, using thrombin and some of its aptamers as a model system. Thrombin, essential in blood coagulation, interacts with its aptamers at distinct binding sites with varying affinities, which we seek to characterize on a single molecule basis.
By tracking binding events of fluorescently labeled thrombin using total internal reflection fluorescence microscopy, we extracted kinetic rate constants of binding and unbinding to different aptamers. For this, we built a robust data analysis procedure, incorporating techniques from PAINT image-processing, machine learning and kinetic modeling to mitigate artifacts from unspecific binding events.
Our comprehensive approach was benchmarked against simulated and experimental data. The insights gained from this study lay the groundwork for future investigations into more complex multivalent binding.

15.30 - 15.50
Samrat Basak, Göttingen, Germany

Three-dimensional multi-target super-resolution microscopy of cells using Metal-Induced Energy Transfer and DNA-PAINT

Samrat Basak1, Nazar Oleksiievets2, Nikolaos Mougios3,4, Daniel C. Jans5,6, Lara Hauke7,8, Jan Christoph Thiele9, Stefan Jakobs5,6,10,11, Felipe Opazo3,12,13, Jörg Enderlein1,11, Roman Tsukanov1

1III. Institute of Physics – Biophysics, Georg August University, 37077 Göttingen, Germany
2Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden.
3Institute of Neuro-and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany.
4International Max Planck Research School for Molecular Biology, 37077 Göttingen, Germany.
5Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
6Department of Neurology, University Medical Center Göttingen, 37073 Göttingen, Germany.
7Institute of Pharmacology and Toxicology, University Medical Center, University of Göttingen, 37079 Göttingen, Germany.
8CIDAS (Campus Institute Data Science), University of Göttingen, 37077 Göttingen, Germany.
9Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K.
10Translational Neuroinflammation and Automated Microscopy, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, 37073 Göttingen, Germany.
11Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), Georg August University, 37077 Göttingen, Germany.
12Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany.
13NanoTag Biotechnologies GmbH, 37079 Göttingen, Germany.

DNA-points accumulation for imaging in nanoscale topography (DNA-PAINT) is a potent variant of single-molecule localization microscopy (SMLM) which is highly effective for multiplexed super-resolution imaging. It achieves localization precision down to nanometers in the lateral direction. However, its routine axial localization precision is approximately three-fold lower as compared to the lateral localization precision. Recently, a technique known as Metal-Induced Energy Transfer (MIET) has been introduced, offering excellent axial resolution at the nanometer scale up to 200 nm above a surface. MIET is characterized by a low entry barrier, as its sole technical requirement is the availability of a fluorescence lifetime imaging modality. In this study, we harness the synergy between the exceptional axial resolution provided by MIET and the lateral resolution achieved with DNA-PAINT (MIET-PAINT) to accomplish multi-target 3D super-resolution imaging. We implemented MIET-PAINT using a wide-field fluorescence lifetime imaging microscope. We validated our technique by measuring the height of emitters placed on top of spacers of known thicknesses. We then demonstrated multiplexed MIET-PAINT imaging of fixed cells to visualize mechanotransduction proteins in the focal adhesion complex (FAC) and the cytoskeleton. We explored the structural arrangement of paxillin, zyxin, and actin stress fibers in U2OS cells and discovered that MIET-PAINT can reliably address multiple targets, providing lateral and axial nanometer-scale resolution. Furthermore, MIET-PAINT can be implemented using confocal microscope equipped with fast scanner, for example Luminosa from PicoQuant GmbH. Preliminary data will be shown.


Oleksiievets, N., Mougios, N., et al. “Three-dimensional multi-target super-resolution microscopy of cells using Metal-Induced Energy Transfer and DNA-PAINT” BiorXiv, (2024)

15.50 - 16.10
Asima Nayak, Berlin, Germany (Student Award)

Characterization of Lewy Body-like Structures in Cellular System and Patient Samples

Asima Nayak1,5, Roberto Sansevrino1, Jian-Hua Chen2,3,4, Christian Hoffmann1, Aleksandr Korobeinikov1, Paula Brosius1, Axel Ekman2,3,4, Joshua Jackson6, Gerard Aguilar Pérez1, Han Wang1, Johannes Vincent Tromm1, Mark A Le Gros2,3,4, Daniele Bano6, Pallavi Gopal5, Carolyn Larabell2,3,4, Dragomir Milovanovic1,2

1Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
2National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA 94740, USA
3Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94740, USA
4Department of Anatomy, University of California San Francisco, San Francisco, CA 94115, USA
5Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA
6German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany

The presence of proteinaceous inclusions known as Lewy bodies (LBs) is a hallmark of Lewy body disorders, characterized by abnormal protein deposits primarily composed of α-synuclein. These deposits disrupt neuronal function, leading to cognitive and motor deficits and ultimately cause cell death. While immunohistochemical studies and mass spectrometry identified nearly three hundred different proteins in LBs, including mitochondria-related proteins and components of the ubiquitin-proteasome system, the biogenesis of LBs remains unclear. Recently, we reverse engineered Lewy body-like inclusions (LBLs) in cellular system. Immunohistochemical studies of patient LBs and LBLs demonstrate that both share a core-shell architecture, where α-synuclein forms a dense shell surrounding a core containing various proteins and membrane-bound organelles. This structural similarity is further supported by soft X-ray tomography and live-cell imaging, which reveal that both LBs and LBLs accumulates mitochondria at their interface. Additionally, the dynamic interactions between α-synuclein and membrane-bound organelles in LBLs mimic those observed in patient LBs, indicating that the processes governing their formation and maturation are likely conserved. These findings highlight the potential of LBLs as cellular models for studying LB architecture and developing novel therapeutic strategies.


[1] M.G. Spillantini, M.L. Schmidt, V.M.-Y. Lee, J.Q. Trojanowski, R. Jakes, M. Goedert, Nature, 388, 839-40 (1997).

[2] K. Wakabayashi, K. Tanji, K. Mori, T. Takahashi, H. Takahashi, Mol Neurobiol, 47, 495-508 (2013).

[3] L. Stefanis, Csh Perspect Med, 2, a009399 (2012).

[4] C. Hoffmann, R. Sansevrino, G. Morabito, C. Logan, R.M. Vabulas, A. Ulusoy, M. Ganzella, D. Milovanovic, J Mol Biol, 433, 166961 (2021).

[5] T.E. Moors, D. Milovanovic, J Parkinsons Dis, 14, 17-33 (2024).

16.10 - 16.20VOTING STUDENT AWARD
16.20 - 16.55COFFEE BREAK & EXHIBITION
16.55 - 18.10POSTER SESSION II
18.30 - …WORKSHOP DINNER
FRET II SessionSuzanne Blum
09.00 - 09.35
Emmanuel Margeat, Montpellier, France (Invited Talk)

Dissecting the structural dynamics of a GPCR using smFRET

Robert Quast1, Leo Bonhomme1, Caroline Clerté1, Ecenaz Bilgen2, Don Lamb2, Philippe Rondard3, Jean Philippe Pin3, Emmanuel Margeat1

1Centre de Biologie Structurale (CBS), Univ. Montpellier, CNRS, INSERM, Montpellier, France
2Department of Chemistry and Center for NanoScience, Ludwig-Maximilians University Munich, Munich, Germany
2Institut de Genomique Fonctionelle, Univ. Montpellier, CNRS, INSERM, Montpellier, France

Metabotropic glutamate receptors (mGluR) regulate neuronal excitability and synaptic transmission by sensing L-glutamate – the major excitatory neurotransmitter in the central nervous system. Their crucial role for synaptic function makes them attractive targets for the treatment of numerous neurological and psychiatric diseases including for instance anxiety, depression, schizophrenia and addiction. To explore mGluR activation, we used single molecule FRET, as it allows to screen the conformations explored by single protein complexes, with high temporal and spatial resolution. However, smFRET is generally limited to one dimensional observations, ie a single distance per protein. 3 color single-molecule FRET extends the conformational analysis to the measurements of 3 distances simultaneously, and therefore to the observation of correlated movements. However, the site-specific labeling of a biomolecular complex with 3 single molecule-compatible fluorophores remains challenging. Here, we established a series of 2-color and 3-color smFRET sensors, through incorporation of two orthogonally reactive non-canonical amino-acids (ncAA) in response to two different stop codons, together with the addition of a SNAP self-labeling tag. These sensors report on the initial steps of mGluR2 activation, including the reorientation of the upper and the lower lobes of the venus flytrap domain (VFT) in an intersubunit fashion, its closure in an intrasubunit fashion [1,2], and the correlation between these 2 movements. We then used 2- and 3-color FRET on single diffusing molecules with time-resolved detection to explore ligand induced conformational changes on mGlu2 receptors. We show that agonist-binding efficiently depopulates the inactive state, leading to an equilibrium of receptors switching between the active and a newly identified intermediate state. Only the addition of a synthetic allosteric modulator, or of the G-protein, leads to a full stabilization of the activated receptor. Our study highlights the power of minimally invasive, ncAA-based, bioorthogonal labeling to dissect domain-specific conformational rearrangements of single, multidomain, multimeric proteins using smFRET.


[1] Quast et al., Nature Communications, 2021, doi.org/10.1038/s41467-021-25620-5

[2] Quast et al., Science Advances, 2023, doi.org/10.1126/sciadv.adf1378

09.35 - 09.55
Nicola Galvanetto, Zurich, Switzerland

Observing protein dynamics in biomolecular condensates with single-molecule spectroscopy

Nicola Galvanetto1, Miloš T. Ivanović1, Aritra Chowdhury1, Andrea Sottini1, Simone del Grosso1, Mark Nuesh1, Daniel Nettels1, Robert Best2, Ben Schuler1

1University of Zurich, Zurich, Switzerland
2Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA

A wide range of biomolecules in solution can phase-separate and form membraneless organelles in the cell. These assemblies often have liquid-like properties, and the corresponding dynamics and exchange of molecules with the environment are important for biological function. The dynamics and materials properties of these systems are commonly assessed based on translational diffusion or rheological properties, typically covering timescales of milliseconds and longer. However, information on the structure and dynamics at the molecular level is lacking. Using coacervates of two disordered highly oppositely charged proteins as a prototypical example of phase separation similar to that observed in the cell nucleus, we show with single-molecule fluorescence spectroscopy that the proteins in the condensates remain disordered, and that their chain dynamics occur on a sub-microsecond timescale, remarkably close to the dynamics in dilute solution [1]. This is despite the condensate being 1000-times more concentrated and 250-times more viscous than the dilute solution. The experimental results are in good agreement with large-scale all-atom molecular dynamics simulations, which reveal the molecular origin of the rapid dynamics.


[1] Galvanetto et al., Nature, 619, 876–883 (2023)

09.55 - 10.15
Daniel Nettels, Zürich, Switzerland

Disordered linkers enable complex motion of two-domain proteins on double-stranded RNA

Oliver Stach1, Sebastian König1, Andrea Holla1, Grégoire Masliah2, Sebastian Doden1, Franziska Zosel1, Maxim Yulikov3, Gunnar Jeschke3, Frédéric H. Allain2, Daniel Nettels1, Benjamin Schuler1,4

1University of Zurich, Department of Biochemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
2ETH Zurich, Institute of Biochemistry, 8093 Zürich, Switzerland
3ETH Zurich, Laboratory of Physical Chemistry, 8093 Zürich, Switzerland
4University of Zurich, Department of Physics, Winterthurerstrasse 190, 8057 Zurich, Switzerland

Double-stranded RNA-binding proteins (dsRBPs) specifically recognize double-stranded RNA in various contexts of post-transcriptional gene regulation [1]. They typically consist of multiple folded dsRNA-binding domains separated by long disordered linkers. In this study, we used single-molecule fluorescence spectroscopy to unravel the complex dynamic interaction of the dsRBP TRBP with dsRNA. TRBP plays a critical role in the RNA interference pathway, where it interacts with Dicer to facilitate the processing of pre-microRNA.[2-4]

Using two- and three-color single-molecule FRET experiments, we resolved and characterized the kinetics of processes occurring over a wide range of timescales from microseconds to hours; including the diffusive motion of TRBP along the RNA on the second timescale; the motion of its domains relative to each other on the millisecond timescale; the flipping of orientations on the RNA on the millisecond timescale; and the full dissociation of the protein from the RNA on the seconds-to-hours timescale.

By combining our single-molecule data with structural information from nuclear magnetic resonance (NMR) spectroscopy [2], maximum entropy ensemble reweighting, and extensive kinetic modeling, we were able to reduce these various complex behaviors of TRBP on dsRNA to a basic mechanism of single-domain association and dissociation on the microsecond to millisecond timescale.


[1] Wilson R. C., Doudna J. A.,  Annu Rev Biophys 42, 217-239 (2013)

[2] Masliah G., Maris C., Konig S. L., Yulikov M., Aeschimann F., Malinowska A. L. Allain F. H., EMBO J 37  (2018)

[3] Koh H. R., Kidwell M. A., Ragunathan K., Doudna J. A., Myong S., Proc Natl Acad Sci U S A 110, 151-156 (2013)

[4] Koh H. R., Kidwell M. A., Doudna J., Myong S. , J Am Chem Soc 139, 262-268 (2017)

10.15 - 10.35
Rana Mhanna, Saarbrücken, Germany

UNEXPECTED EFFECT OF EXCITATION WAVELENGTH IN SINGLE-MOLECULE PHOTOCHEMISTRY OF TERRYLENE

Rana Mhanna1, Julia Berger2, Gregor Jung3

1rana.mhanna@uni-saarland.de
2julia.berger@uni-saarland.de
3g.jung@mx.uni-saarland.de

Single-molecule chemistry (SMC) by means of fluorescence microscopy allows us to study a reactive system at the molecular scale, providing deep and unique insights that cannot be revealed in bulk. Among the imaging techniques, especially Total Internal Reflection Fluorescence (TIRF) microscopy is nowadays most commonly used, as it permits the analysis of molecular processes at or near the surface of the sample in a parallelized way, including a high signal-to-noise ratio. Our approach in SMC is to monitor changes of fluorescence properties during the reaction1, and in the current case, we study the fluorescence colour change during the photooxidation of terryleneusing TIRF microscopy. Actually, terrylene is the ideal compound for single-molecule fluorescence chemistry owing to its luminescent properties, photostability and its ability to be embedded in solid matrices3. We report herein a comparative study between two excitation wavelengths on a population of approximately 100 reacting terrylene molecules for each condition. This study not only reveals the quantum yield for the photooxidation and the lifetime of the intermediate but also an unexpected effect of the excitation wavelength on promoting one reaction pathway over another. Our finding will be discussed with respect to findings in ultra-fast spectroscopy.


[1] A. Rybina, C. Lang, M. Wirtz, K. Grußmayer, A. Kurz, F. Maier, A. Schmitt, O. Trapp, G. Jung, D. P. Herten, Angew. Chem. Int. Ed. 2013, 52, 6322–6325.

[2] T. Christ, F. Kulzer, P. Bordat, T. Basché, Angew. Chem. Int. Ed. 2001, 40, 4192-4195.

[3] S. Kummer, F. Kulzer, R. Kettner, T. Basché, C. Tietz, C. Glowatz, C. Kryschi, J. Chem. Phys. 1997, 107, 7673-7684.

10.35 - 10.45STUDENT AWARD PRESENTATION
10.45 - 11.20COFFEE BREAK & EXHIBITION
Biological Applications SESSIONAnindya Datta
11.20 - 11.50
Suzanne A. Blum, Irvine, United States (Invited Talk)

Chemical Reaction Insights through FLIM

Suzanne A. Blum

University of California, Irvine, USA

My laboratory is fascinated by understanding how chemical reactions work. Without the right tools to investigate chemical reactions, critical details are missed. Thus, my laboratory is also fascinated by tool development. Here the development of FLIM application methods provides the ability to simultaneously image physical and chemical changes inside of polymers in real time during catalytic polymerization. FLIM enables not only an understanding of the dynamic chemical and physical changes inside polymers as they are growing with high spatiotemporal resolution, but also how these two features impact each other and catalytic turnover. Case studies in ring-opening metathesis polymerization (ROMP) include development of spectroscopic (fluorescence-lifetime-imaging) methods for the determination of the molecular weights of growing polymers during ongoing reactions, identification of the causes of assembly–disassembly processes in block-copolymers at the individual-block level, and pinpointing the impact of real-time changing physical parameters inside growing polymers on the catalytic chemical reactivity of monomer insertion and polymer growth. The impact of these microscopic behaviors on macroscopic material properties leads to opportunities for improvement in catalyst efficiency and in tailoring bulk polymer properties.

11.50 - 12.10
Melissa Birol, Berlin, Germany

Early deviations in cell-to-cell communication in neurodegenerative disease trajectories 

Anna Oliveras Martinez, Paula Santos-Otte, Guido Mastrobuoni, Agnieszka Rybak-Wolf, Stefan Kempa, Melissa Birol

Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany.

Aberrant lipid metabolism is emerging as a central component, interfacing with all major facets of neurodegenerative diseases (NDs)[1]. These include pathological hallmarks of intracellular deposits of intrinsically disordered proteins (IDPs) and their high spatiotemporal pattern of progression through the brain[2,3]. It is unclear when and how protein propagation initiates and what defines cellular vulnerability to spread IDPs throughout the brain. In our group we question how the redistributed lipidome in Alzheimer’s and Parkinson’s disease brains affect IDP functions and influence their spreading kinetics both in neurons and in surrounding glia. We monitor changes in lipid metabolism and IDP functions to enable the discovery of common nodes and targetable pathways applicable for early intervention. We probe quantitative cell biology by single-molecule imaging technologies to detect and monitor the evolution of early-stage disease phenotypes. We combine systems level -omics approaches with functional calcium and metabolic imaging to elucidate how misregulation of cellular crosswalks within the brain insult neuronal function. Questions are addressed on different biological scales - from molecular studies to patient derived induced pluripotent stem cell 2D co-/cultures and 3D brain organoids, to map early events that initiate propagation trajectories and connect modulation of specific lipid metabolic pathways to IDP-induced proteinopathies.


1. Estes RE, Lin B, Khera A, Davis MY (2021) Lipid metabolism influence on neurodegenerative disease progression: is the vehicle as important as the cargo? Front Mol Neurosci 14:788695

2. Calafate S., Buist A., Miskiewicz K., Vijayan V., Daneels G., de Strooper B., et al. (2015). Synaptic contacts enhance cell-to-cell Tau pathology propagation. Cell Rep. 11 1176–1183. 10.1016/j.celrep.2015.04.043

3. Birol, M., Wojcik, S.P., Miranker, A.D. and Rhoades, E., 2019. Identification of N-linked glycans as specific mediators of neuronal uptake of acetylated α-Synuclein. PLoS Biology, 17(6), p.e3000318.

12.10 - 12.30
Johannes Broichhagen, Berlin, Germany

Heavier fluorophores with boosted brightness, lifetime and stability

Johannes Broichhagen

Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Roessle-Str. 10, Berlin/D

Chromophores are setting benchmarks in the life sciences to visualize biomolecules and to optically control biological function. Organic chemistry is at the forefront in designing, synthesizing and applying small molecule fluorophores for better image quality and higher sensitivity. We present the introduction of deuterium into fluorescent dyes to boost brightness, photostability and lifetime. With a color palette in hand from red to the near-infrared spectrum, we showcase super-resolution imaging and single molecule detection. Hand in hand with different tagging strategies, we aim to explore the localization and behaviour of cell surface proteins that play crucial roles in neurodegenerative disease.  

12.30 - 12.50
Michael Börsch, Jena, Germany

Beyond smFRET - NV qubit in nanodiamond for monitoring subunit rotation in single FoF1-ATP synthase

Iván Pérez, Lukas Spantzel, Fahimeh Rashidi, Thomas Heitkamp, Michael Börsch

Single-Molecule Microscopy Group, Nonnenplan 2, 07734 Jena

Nitrogen-vacancy (NV) centers in nanodiamonds (10 to 100 nm diameter) can be applied as single fluorescent quantum sensors. The surface of nanodiamonds can be tailored for specific binding to biological targets. The extraordinary photo-physical properties such as very high photo-stability and non-blinking behaviour allow for optical detection of magnetic resonance of the NV triplet spin states [1] and nanoscale distance measurements. Taking advantage of the extended observation times using our version of a confocal anti-Brownian electrokinetic trap (ABEL trap [2]), we determined molecular brightness, spectral ratio, diffusion coefficient, surface charge and multiexponential fluorescence lifetimes for each nanodiamond one by one in solution [3].

The goal of our quantum-sensing project (with A. Krueger, J. Wrachtrup, F. Jelezko) is to exploit the spin properties of the luminescent NV- center to reveal the dynamics of biological systems. For 25 years we have studied subunit rotation of the membrane enzyme FoF1-ATP synthase in solution by intramolecular single-molecule FRET, with increased observation times for about a second in the ABELtrap [4]. Now, monitoring fluorescence lifetime changes of the NV- center due to the Zeeman effect of local magnetic fields enables us to record conformational changes of a diffusing single protein for tens of seconds.


[1] C. Laube et al., Nanoscale, 11, 1770-1783 (2019).

[2] A. E. Cohen, W. E. Moerner, Proc. Natl. Acad. Sci. U. S. A., 103, 4362–4365 (2006).

[3] I. Pérez, A. Krueger, J. Wrachtrup, F. Jelezko, M. Börsch, Proc. of SPIE, 12849, 1284906 (2024).

[4] I. Pérez, T. Heitkamp, M. Börsch, Intl. J. Mol. Sci., 24, 8442 (2023).

12.50 - 14.20LUNCH BREAK
Correlation Spectroscopy SESSIONEmmanuel Margeat
14.20 - 14.50
Anindya Datta, Mumbai, India (Invited Talk)

Elucidation of exciton dynamics in semiconductor nanocrystals using Fluorescence Lifetime Correlation Spectroscopy 

Anindya Datta

Indian Institute of Technology, Bombay, Mumbai, India

Fluorescence correlation spectroscopy has been used to investigate the photoprocesses in two kinds of nanocrystals, namely 3-mercaptopropionic acid (3-MPA) capped Cu(I)-doped CdS (Cu:CdS)1 and Copper Indium Sulphide (CIS)2 quantum dots (QDs). Photoactivation of the Cu:CdS QDs via dim/dark to bright particle conversion is observed at higher excitation powers. Dispersive blinking1 kinetics in undoped QDs reflects the involvement of a broad distribution of trap states. A lesser extent of dispersity is observed for doped QDs, in which the hole-capture by the Cu-defect states predominates. Excitation fluence dependence of blinking rate highlights the role of Auger recombination in undoped QDs, which is suppressed significantly upon doping, due to disruption of electron-hole correlation. On the other hand, for the CIS QDs, an unusual excitation wavelength-dependence of photoactivation / photocorrosion is manifested in the increase in the initial correlation amplitude G(0) for λex= 532 nm, but decrease for λex = 405 nm. This has been rationalized in terms of different contributions from surface-assisted recombination in the two cases. Blinking times obtained from the Autocorrelation Functions (ACF) of the 100-200 ns lifetime component (core Cu-mediated recombination) are almost unaffected by shelling, but those from the ACF for the 10-30 ns lifetime (surface states) increases significantly. Absence of cross-correlation between the two recombinative states of bare CIS QDs and the emergence of an anticorrelation with the introduction of ZnS shell is observed, indicating the diffusive nature of the two states for CIS-ZnS. The diffusion is inhibited in base CIS QDs due to the preponderance of surface states. On a different note, blinking dynamics in FAPbBr3 perovskite nanocrystals have been analysed using Change Point Analysis (CPA), to throw light upon the involvement of a cluster of states.3


1 Das S, Rana G, Ali F and Datta A. Nanoscale, 2023, 15, 4469-4476 2 Singha P. K., Kistwal T and Datta A. J. Phys. Chem. Lett., 2023, 14, 4289-4296. 3Singha, P. K., Mukhopadhyay T., Tarif E., Ali F. and Datta A., J. Chem. Phys. 2024, 161, 054704.

14.50 - 15.10
Tanuja Kistwal, Bochum, Germany

Fluorescence correlation spectroscopy of Single wall carbon nanotubes

Tanuja Kistwal, Chen Ma, Sebastian Kruss

Department of Chemistry, Ruhr-University Bochum, Germany

Fluorescence Correlation Spectroscopy (FCS) is a non-invasive method that analyzes temporal fluctuations in fluorescence intensity and provides access to molecular information at the single molecule level [1]. Here, we implement near-infrared (NIR) FCS to understand the dynamics of single-walled carbon nanotubes (SWCNTs) based fluorescent biosensors [2]. We explore the intricate interactions between individual analyte molecules and DNA-functionalized SWCNTs, which act as model biosensors for biomolecules like the neurotransmitter dopamine. By tracking the diffusion of individual SWCNTs, we uncover new insights into molecular recognition. In this study, we employed FCS measurement using a modified confocal microscope capable of time correlated single photon counting (TCSPC) to determine cross-correlation functions of SWCNTs and their modulation in response to analyte molecules. The SWCNTs were excited at a wavelength of 480 nm and emission was detected in the near-infrared (NIR) region above 900 nm using single-photon avalanche detectors (SPAD). We present diffusion constants using power variation and illustrate their alteration due to molecular binding events. These findings not only advance our fundamental understanding of single-walled carbon nanotube (SWCNT) photophysics and their associated dynamics but also have profound implications for biophysics and materials science.


[1]       E. L. Elson, Biophys. J., 101, 2855–2870 (2011).

[2]       J. Ackermann, J. T. Metternich, S. Herbertz, S. Kruss, Angew. Chem. Int. Ed. Engl., 61, e202112372 (2022).

15.10 - 15.30
Sebastian Kruss, Bochum, Germany

Near infrared fluorescent nanosensors for biomedical imaging

Sebastian Kruss

Ruhr University Bochum, Universitätsstrasse 150, 44801 Bochum

Near infrared (NIR, 800 nm -1700 nm) fluorescence imaging promises ultra-low background and scattering (tissue transparency window). We use nanomaterials such as NIR fluorescent single-walled carbon nanotubes (SWCNTs) as building blocks for advanced sensors/probes. 

Here, I will present novel approaches to extract more information from their fluorescent signals and applications in bioimaging. Fluorescence lifetime imaging microscopy (FLIM) of SWCNT-based sensors is introduced as absolute and calibration-free NIR imaging method for biomolecules. This technique is enabled by laser scanning confocal microscopy (LSCM) optimized for NIR signals (>800 nm) and time correlated single photon counting (TCSPC). Moreover, the potential of spectral phasor approaches is discussed, and how it enables fast multispectral NIR imaging and multiplexing. Such sensors are shown to detect (bio)molecules over multiple length and time scales: From single proteins and single signaling molecules (neurotransmitters) released from networks of cells to molecular profiles of pathogens or  stress (reactive oxygen species) in plants.1-4


[1] Sistemich et al. Angew. Chem. Int. Ed. 2023

[2] Metternich et al. JACS 2023

[3] Ma et al. Nano Letters 2024

[4] Settele et al. Nature Communications 2024

15.30 - 15.50
Tjaart Krüger, Pretoria, South Africa

Comparison of real-time feedback-driven single-particle tracking techniques

Bertus van Heerden, Tjaart Krüger

Department of Physics, University of Pretoria, South Africa

One of the main challenges in studying single biomolecules in a native or near-native environment is their diffusive motion. Real-time feedback-driven single-particle tracking (RT-FD-SPT) overcomes this limitation by using feedback control to keep a particle of interest in the detection volume. RT-FD-SPT offers a marked improvement in the 3D spatiotemporal resolution compared to image-based SPT and additionally enables an extended tracking time and region and the ability to perform concurrent spectroscopic measurements on the tracked molecules. Selection of the most appropriate RT-FD-SPT method for a particular application has thus far been hindered by a lack of objective, systematic comparisons. We have developed a theoretical approach, based on statistical calculations and dynamical simulations, to objectively compare three commonly used RT-FD-SPT methods, viz., the orbital, knight’s tour, and MINFLUX methods [1]. We also compared the performance of two photon sources – fluorescence and interferometric scattering (iSCAT) – to labelled and autofluorescent biological samples. Our results indicate a fundamental trade-off between precision and speed [1,2]. Finally, we demonstrate our experimental implementation of RT-FD-SPT on aggregates of the main light-harvesting pigment-protein complex of plants to correlate their size, spectra, and fluorescence lifetimes, revealing new size–function relationships in the context of photoprotection.


[1] B. van Heerden, T.P.J. Krüger, J. Chem. Phys., 157, 084111 (2022).

[2] B. van Heerden, N.A. Vickers, T.P.J. Krüger, S.B. Andersson, Small, 18, 2107024 (2022).

15.45 - 16.00Concluding Remarks
16.00 - End of Workshop
Julia Berger, Saarbrücken, Germany

P1: Single-Molecule Spectroscopy of the Excited-State Proton Transfer

Julia Berger, Gregor Jung

Saarland University, Campus B 2.2, 66123 Saarbrücken

Single-molecule spectroscopy applied to chemical reactions can reveal competing reaction pathways or micro-heterogeneities in the sample that remain hidden in ensemble studies.[1] Excited-state proton transfer (ESPT) is the only photochemical reaction which is compatible with fluorescence and therefore appears particularly suitable for single-molecule studies: Electronic excitation of a so-called photoacid leads to the release of a proton in the excited state and after emission, reprotonation takes place in the ground state.[2,3] This photocycle allows for studying one individual molecule and its proton transfer reaction repeatably. By embedding highly fluorescent and photostable photoacid molecules[4] in non-fluorescent solid phosphine oxide matrices, intermediates in the ESPT can be studied using total internal reflection fluorescence microscopy (TIRFM). Spectra of the single photoacid/phosphine oxide complexes can be recorded by adding a transmission grating in front of the CMOS-camera.[5] Deconvolution of the obtained single-molecule spectra then allows us to derive the population of the different intermediates[6] providing information about the heterogeneity of the surrounding polarity in a solid, polar, aprotic matrix.


Literature:

[1] A. Rybina, C. Lang, M. Wirtz, K. Grußmayer, A. Kurz, F. Maier, A. Schmitt, O. Trapp, G. Jung, D.-P. Herten, Angew. Chem. Int. Ed., 52, 6322-6325 (2013).

[2] M. Vester, T. Staut, J. Enderlein, G. Jung, J. Phys. Chem. Lett., 6, 1149-1154 (2015).

[3] M. Vester, A. Grueter, B. Finkler, R. Becker, G. Jung, Phys. Chem. Chem. Phys., 18, 10281 (2016).

[4] B. Finkler, C. Spies, M. Vester, F. Walte, K. Omlor, I. Riemann, M. Zimmer, F. Stracke, M. Gerhards, G. Jung, Photochem. Photobiol. Sci., 13, 548-562 (2014).

[5] M. N. Bongiovanni, J. Godet, M. H. Horrocks, L. Tosatto, A. R. Carr, D. C. Wirthensohn, R. T. Ranasinghe, J.-E. Lee, A. Ponjavic, J. V. Fritz, C. M. Dobson, D. Klenerman, S. F. Lee, Nat. Commun., 7, 1-9 (2016).

[6] A. Grandjean, J. L. Pérez Lustres, S. Muth, D. Maus, G. Jung, J. Phys. Chem. Lett., 12, 1683-1689 (2021).

Ekaterina Bestsennaia, Geneva, Switzerland

P2: Water-sensing fluorophores targeting organelles in living cells

Ekaterina Bestsennaia, Laure Maistre, Nicolas Borgnana, Liza Briant, Alexandre Fürstenberg

Department of Physical Chemistry and Department of Inorganic and Analytical Chemistry, University of Geneva, 1211 Geneva, Switzerland

Red-emitting fluorophores are widely used for imaging living systems as the red part of the spectrum is less photodamaging and better transmitted in biological samples. At the same time, these fluorophores are known to be quenched by surrounding water molecules [1]. Quenching by water reduces both the fluorescence quantum yield and lifetime of such dyes so that the dye's direct hydration can be assessed by monitoring changes in its lifetime [2]. In this work, we develop and use derivatives of a water-sensing red-emitting fluorophore specifically targeted to different organelles in living cells. We perform fluorescence lifetime imaging (FLIM) to visualize variations in the local hydration of the probe within different organelles. Characterizing the label's hydration properties opens perspectives for using these labels as water-sensing probes in functional imaging of cellular processes. Upcoming use of these probes in fluorescence lifetime single-molecule localization microscopy (FL-SMLM) [3] will enable the detection of local hydration heterogeneities at the nanoscale.


[1] Maillard, J., Klehs, K., Rumble, C., Vauthey, E., Heilemann, M., & Fürstenberg, A., Chemical Science, 12(4), 1352–1362 (2021)

[2] Maillard, J., Rumble, C. A., & Fürstenberg, A., The Journal of Physical Chemistry. B, 125(34), 9727–9737 (2021)

[3] Thiele, J. C., Helmerich, D. A., Oleksiievets, N., Tsukanov, R., Butkevich, E., Sauer, M., Nevskyi, O., & Enderlein, J, ACS Nano, 14(10), 14190–14200 (2020)

Mihai Adrian Bodescu, Berlin, Germany

P3: Studying intrinsically disordered proteins from the endocytic uptake machineryby integrated NMR and single molecule FRET

Samuel Naudi-Fabra1, Mihai Adrian Bodescu2, Sigrid Milles3

1Naudi-Fabra@fmp-berlin.de
2bodescu@fmp-berlin.de
3milles@fmp-berlin.de

Intrinsically disordered proteins (IDPs) lack clearly defined structure and are therefore highly flexible and easily adaptable to different binding partners. However, their dynamic features and broad range of interaction modes render them difficult to study and analyzing their complexes often requires integrated approaches. We have recently developed an approach to calculate conformational ensembles of IDPs using Förster resonance energy transfer (FRET) efficiencies acquired on the single molecule level together with NMR parameters (chemical shifts, paramagnetic relaxation enhancements - PREs). We have bench-marked this approach with a large set of in silico FRET efficiencies and NMR PREs, which we then validated with experimental FRET, fluorescence lifetime and NMR data [1].

We now apply this strategy to study the conformational landscape of intrinsically disordered proteins involved in the pathway of clathrin mediated endocytosis. The early phases of clathrin mediated endocytosis are organized through a highly complex interaction network mediated by clathrin associated sorting proteins (CLASPs) that comprise long intrinsically disordered regions (IDRs), which interact with various partners. Using single molecule FRET, we characterize the long-range inter- and intra-molecular interactions within this IDR-network and aim at integrating those data using NMR parameters with the goal to generate a molecular picture of endocytosis onset.


[1] Naudi-Fabra, S., Tengo, M., Jensen, M. R., Blackledge, M. & Milles, S. Quantitative Description of Intrinsically Disordered Proteins Using Single-Molecule FRET, NMR, and SAXS. J Am Chem Soc 143, 20109–20121 (2021).


 

Bo Volf Brøchner, Aarhus C, Denmark

P4: Direct measurements of α-synuclein oligomers display pore-like activity modulated by lipid membrane charge and curvature

Bo Volf Brøchner, Xialin Zhang, Janni Nielsen, Jørgen Kjems, Daniel E. Otzen, Mette G. Malle

Interdisciplinary Nanoscience Center, Aarhus University, Aarhus C, 8000, Denmark

Parkinson's disease (PD) is a progressive neurodegenerative disorder marked by the loss of dopaminergic neurons and the accumulation of alpha-synuclein protein, forming toxic oligomers and fibrils. These cytotoxic alpha-synuclein oligomers (αSO) possess a pore-like structure, can disrupt cell membranes and is able to release small molecules, contributing to PD's cytotoxic effects [1].

To address the unclear mechanisms of αSO interactions with lipid membranes, we employed a novel single-liposome assay to model these interactions at the single vesicle level [2]. Using single-particle localization, we deconvoluted the contributions of charge and curvature in these interactions and their impact on the release of membrane-encapsulated small molecules. Our findings reveal that αSO membrane association depends on curvature and lipid composition, with density increasing exponentially with negative membrane charge.

We propose a two-step model for αSO membrane interactions: an initial membrane recruitment process followed by a charge-dependent reorientation process. Real-time imaging shows that oligomers fully incorporate into membranes, acting as pores and translocating small molecules. Understanding these interactions is crucial for preventing cellular dysfunction, potentially leading to new therapeutic approaches to stabilize αSO and avoid toxicity.


[1] Giehm, L., et al., Low-resolution structure of a vesicle disrupting α-synuclein oligomer that accumulates during fibrillation. 
    Proceedings of the National Academy of Sciences. 108(8): p. 3246-3251. (2011)

[2] Malle, M. G. et al. Single-particle combinatorial multiplexed liposome fusion mediated by DNA. Nat. Chem. 14, 558–565 (2022).

Niclas Gimber, Berlin, Germany

P5: Simultaneous multicolor DNA-PAINT without sequential fluid exchange using spectral demixing

Niclas Gimber, Jan Schmoranzer

Advanced Medical BIOimaging Core Facility, Charité – Universitätsmedizin Berlin, 10117 Germany

Several variants of multicolor single-molecule localization microscopy (SMLM) have been developed to resolve the spatial relationship of nanoscale structures in biological samples. The oligonucleotide-based SMLM approach ‘DNA-PAINT’ robustly achieves nanometer localization precision and can be used to count binding sites within nanostructures. However, multicolor DNA-PAINT has primarily been realized by ‘Exchange-PAINT’ that requires sequential exchange of the imaging solution and thus leads to extended acquisition times. To alleviate the need for fluid exchange and to speed up the acquisition of current multichannel DNA-PAINT, we here present a novel approach that combines DNA-PAINT with simultaneous multicolor acquisition using spectral demixing (SD). By using newly designed probes and a novel multichannel registration procedure we achieve simultaneous multicolor SD-DNA-PAINT[1] with minimal crosstalk. We demonstrate high localization precision (3 – 6 nm) and multicolor registration of dual and triple-color SD-DNA-PAINT by resolving patterns on DNA origami nanostructures and cellular structures.


1.     Gimber, N., Strauss, S., Jungmann, R., Schmoranzer, J., 2022. Simultaneous Multicolor DNA-PAINT without Sequential Fluid Exchange Using Spectral Demixing. Nano Letters. 22, 2682–2690. https://doi.org/10.1021/acs.nanolett.1c04520

Ivan Gligonov, Göttingen, Germany

P6: Variational calculus approach to Zernike polynomials with application to fluorescence correlation spectroscopy.

Ivan Gligonov, Jörg Enderlein

Third Institute of Physics – Biophysics, Georg August University, 37077 Göttingen, Germany

Zernike polynomials, introduced in 1934, are crucial in optics for modeling microscopy systems and describing wavefront aberrations. Despite their importance, their theoretical foundations are often overlooked. This research aims to develop a new derivation approach using variational calculus, establishing a connection between Zernike polynomials and Bessel functions.

The study applies these polynomials to analyze aberrations in fluorescence microscopy, focusing on their effects on Point Spread Function (PSF) shape and Fluorescence Correlation Spectroscopy (FCS) curves. Using electrodynamic principles, experiments were modeled with fluorophores as oscillating dipoles and microscopes as low-pass filters. MATLAB was used for numerical calculations.

Results reveal the impact of aberrations on estimated diffusion time, with a curious finding that two-photon excitation is more affected by aberrations than one-photon excitation. This challenges the common belief that two-photon techniques are inherently more precise.

This research contributes to a deeper understanding of optical system modeling and highlights the importance of considering aberrations in interpreting microscopy results, potentially influencing future experimental designs and data analysis in the field.

John Gonzalez-Murillo, West Lafayette, United States

P7: Fluorescence Intensity and time domain analysis by Time Correlated Multi-Photon Counting (TCMPC).

Masanobu Yamamoto1, John Gonzalez-Murillo2, Keegan Hernandez1, J.Paul Robinson1

1Miftek Corporation,1231 Cumberlland Ave., West Lafayette, In 47906, United States of America
2Argamasilla de Calatrava, C.P 13440, Ciudad Real, Spain

Fluorescence behavior of new materials differ from traditional fluorochromes. Developed Time Correlated Multi-Photon Counting (TCMPC) system provides a powerful tool to study emission intensity, time response and dynamics at the individual quantum molecular response level.

The aim is to present experiments on photon spectroscopy, fluorescence intensity and lifetime decay using the TCMPC and Successive Molecular Decay (SMD) techniques.

Fluorescence time domain experiments were conducted using fluorochromes and quantum dots. We analyzed the quantum dynamic response of samples after the analog-recording of the photons detected with our developed TCMPC system.

The photon counting rate of our TCMPC system ranges up to 1Gcps with minimized death time. Due its high counting rate, it is possible to capture data not only for the first detected photon but also for consecutive photons in the same laser excitation period. This allows to observe the dynamic behavior and quantum efficiency during the ground, excitation, stabilization and decay states of the samples.

Findings shown most of the organic fluorochromes exhibited shorter lifetimes and faster stabilization after excitation. However, quantum multidots showed longer lifetimes and delayed emission. Both TCMPC and SMD techniques provide simultaneous intensity and decay information, which could enhance analysis of excitation-electron interactions at molecular level.


References

Acerbi, Fabio, and Stefan Gundacker. "Understanding and Simulating Sipms." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 926,16-35 (2019):

Georgel, Rachel, Konstantin Grygoryev, Simon Sorensen, Huihui Lu, Stefan Andersson-Engels, Ray Burke, and Daniel Hare. "Silicon Photomultiplier—a High Dynamic Range, High Sensitivity Sensor for Bio-Photonics Applications." Biosensors, no. 10 (2022).

Masanobu Yamamoto, John Jaiber González Murillo, Keegan Hernandez, J. Paul Robinson, "Successive molecular decay measurement by time-correlated multiphoton counting (TCMPC)," Proc. SPIE 12863, Quantum Effects and Measurement Techniques in Biology and Biophotonics, 128630D (2024)

Erin M. Hanada, Irvine, United States

P8: Fluorescence Lifetime Imaging Spectroscopy Reveals Potential Reaction Activation Method of Trimethylsilyl Chloride Additives in Zinc Oxidative Addition Reactions

Erin M. Hanada1, Patrick J. McShea2, Suzanne A. Blum2

1Hans-Meerwein-Straße 4, 35043 Marburg, Germany
2Chemistry Department, University of California, Irvine, Irvine, CA 92697–2025 USA

Trimethylsilyl chloride (TMSCl) is commonly used to “activate” metal(0) powders toward oxidative addition of organohalides, but knowledge of its mechanism remains limited by the inability to characterize chemical intermediates under reaction conditions. Here, fluorescence lifetime imaging microscopy (FLIM) overcomes these prior limitations and shows that TMSCl aids in solubilization of the organozinc intermediate from zinc(0) metal after oxidative addition, a previously unknown mechanistic role. This mechanistic role is in contrast to previously known roles for TMSCl before the oxidative addition step. To achieve this understanding, experiments develop FLIM, a tool traditionally used in biology, to characterize intermediates during a chemical reaction—revealing mechanistic steps that are unobservable without fluorescence lifetime data. These findings impact organometallic reagent synthesis and catalysis by providing a previously uncharacterized mechanistic role for a widely used activating agent, an understanding of which is suitable for revising activation models and for developing strategies to activate currently unreactive metals.

Johan Hummert, Berlin, Germany

P9: Widefield and lightsheet lifetime imaging with a novel SPAD camera

Johan Hummert1, Valentin Dunsing-Eichenauer2, Max Tillmann1, Ivan Michel Antolovic3, Claire Chardès2, Thomas Schönau1, Felix Koberling1, Léo Guinard2, Corinna Nock1, Pierre-François Lenne2, Rainer Erdmann1

1PicoQuant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany, info@picoquant.com
2Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
3Pi Imaging Technology SA, EPFL Innovation Park, 1015 Lausanne, Switzerland, info@piimaging.com

Fluorescence lifetime imaging microscopy (FLIM) offers unique advantages, especially for imaging of living cells and organisms. Lifetime based sensors enable functional imaging of, for instance, pH, membrane tension or fluidity, or ion concentration. However, FLIM is typically implemented in confocal microscopy, limiting applicability to living samples due to high local laser power densities and slow frame rates. Faster and gentler imaging would be possible with widefield FLIM, but available FLIM cameras often impose other limitations.

Here we evaluate a novel 512x512 pixel SPAD camera in combination with PicoQuant pulsed lasers. We demonstrate widefield lifetime imaging of commercial cell samples at up to 30 fps. We further demonstrate lightsheet FLIM on a single objective lightsheet microscope for even gentler imaging. This approach enables 3D FLIM on live embryonic organoids including lifetime-based multiplexing, and time-lapse 3D FLIM of mechanosensitive tension probes. The selected applications highlight the potential of the novel hardware for FLIM at unprecedented speed and throughput, providing a powerful tool for functional imaging of dynamic multicellular systems.

Tjaart Krüger, Pretoria, South Africa

P10: Multipurpose GUI-based software package for single-molecule spectroscopic data analysis

Joshua Botha, Bertus van Heerden, Tjaart Krüger

Department of Physics, University of Pretoria, 0002, South Africa

We have developed Full SMS [1], an open-source, multipurpose graphical user interface (GUI)-based software package for analysing single-molecule spectroscopy (SMS) data. SMS typically delivers multiparameter data — such as fluorescence brightness, lifetime, and spectra — of molecular- or nanometre-scale particles such as single dye molecules, quantum dots, or fluorescently labelled biological macromolecules. Full SMS allows an unbiased statistical analysis of fluorescence brightness through level resolution and clustering, analysis of fluorescence lifetimes through decay fitting, as well as the calculation of second-order correlation functions and the display of fluorescence spectra and raster-scan images. Additional features include extensive data filtering options, a custom HDF5-based file format, and flexible data export options. The software is open source and written in Python but GUI-based so it may be used without any programming knowledge. A multi-process architecture was employed for computational efficiency. The software is also designed to be easily extendable to include additional import data types and analysis capabilities.


[1] J.L. Botha, B. van Heerden, T.P.J. Krüger, accepted in Biophys. Rep.  http://github.com/BioPhysicsUP/Full_SMS

Ralf Kühnemuth, Düsseldorf, Germany

P11: An optofluidic antenna for enhancing the sensitivity of single-emitter measurements

Luis Morales-Inostroza1,2,3, Julian Folz4, Ralf Kühnemuth4, Suren Felekyan4, Franz-Ferdinand Wieser1,2,3, Claus A.M. Seidel4, Stephan Götzinger1,3,5, Vahid Sandoghdar1,3

1Max Planck Institute for the Science of Light, 91058 Erlangen, Germany
2Max-Planck-Zentrum für Physik und Medizin, 91058 Erlangen, Germany
3Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
4Chair for Molecular Physical Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
5Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91052 Erlangen, Germany

Many single-molecule optical studies are performed in fluidic environments, e.g., to avoid unwanted consequences of contact with surfaces. The inherent diffusion of molecules in this arrangement limits the observation time and the number of collected photons, thus, compromising studies of processes with both fast and slow dynamics. Here, we introduce a planar optofluidic antenna (OFA), which enhances the fluorescence signal from molecules by up to a factor of 5 per passage, leads to about 7-fold more frequent returns to the observation volume, and significantly lengthens the diffusion time within one passage. We use single-molecule multi-parameter fluorescence detection (sm-MFD), fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) measurements to characterize our OFAs. We then showcase the advantages of the antenna by examining both slow (ms) and fast (50 µs) dynamical behavior of Holliday junctions with real-time resolution. The ease of implementation and compatibility with various microscopy modalities make OFAs broadly applicable to a large variety of studies.

Siyu Lu, München, Germany

P12: Using supramolecular chemistry to establish functional dyes

Siyu Lu1, Justin Neumann2, Andreas Hennig2, Thorben Cordes1

1Physical and Synthetic Biology. Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
2Center for Cellular Nanoanalytics (CellNanOs) and Department of Biology and Chemistry, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany

Many imaging techniques and biochemical assays rely on selective labeling of target structures in vitro and in vivo with commercial fluorophores that have specific yet invariant properties. Consequently, a fluorophore (or dye) is only useful for a limited range of applications, e.g., as a label for cellular compartments, super-resolution imaging, DNA sequencing or for a specific biomedical assay. Modifications of fluorophores with the goal to alter their bioconjugation chemistry, photophysical or functional properties typically require complex synthesis schemes. We recently introduced a general strategy that allows to customize these properties during the labelling process with the goal to introduce the fluorophore in the last step of bio-labeling[1] or to obtain multifunctional dyes via the same scaffold[2]. We here describe unpublished work on the use of supramolecular chemistry to transiently modify fluorophore properties. We characterize different pairs of commercially available hosts and dyes, frequently used for single-molecule detection and super-resolution microscopy[3-4], in light of their interaction, photophysical properties, biophysical and imaging applications.


[1] Zhang et al., Angew. Chem. Int. Ed., e202112959. (2022)  

[2] Y. Li et al., bioRxiv (2024) - https://www.biorxiv.org/content/10.1101/2024.05.24.595706v1.abstract

[3] L. Albertazzi and M. Heilemann, Angew. Chem. Int. Ed. Engl., 62, e202303390 (2023)

[4] F. Kessler et al., Angew. Chem. Int., Ed e202307538 (2022)

Terézia Paulovčáková, Prague, Czech Republic

P13: Single molecule FRET analysis of the role of chromatin-associated protein LEDGF in nucleosome remodelling

Terézia Paulovčáková1,2, Petro Khoroshyy1, Sveinn Bjarnason3, Eliška Bartl Koutná1, Vanda Lux1, Pétur Orri Heiðarsson3, Václav Veverka1,2

1Institute of Organic Chemistry and Biochemistry (IOCB) of the Czech Academy of Sciences, Prague 160 00, Czech Republic
2Department of Cell Biology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
3Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102 Reykjavík, Iceland

Transcription is controlled by epigenetic regulators that modify histones via deposition of epigenetic marks, which are in turn ‘read’ by epigenetic readers, leading to appropriate cellular responses. Lens epithelium-derived growth factor (LEDGF) is an essential epigenetic reader and a transcriptional co-activator. LEDGF is therapeutically important as a host cell cofactor in HIV-1 integration and a key factor in MLL (Mixed lineage leukemia) transformation. It forms complexes with HIV-1 Integrase and chimeric MLL/menin, respectively, via its C-terminal protein-binding domain. It then ‘reads’ the mark of active genes (di-/trimethylated H3K36) and tethers the complexes to active chromatin via its N-terminal PWWP domain. These two domains are linked by the central intrinsically disordered region (IDR). Due to its disorder and flexibility, the protein is difficult to study using traditional structural biology methods. Nucleosome core particle is a good fit for smFRET analyses as its dimensions correspond with FRET sensitivity range. Two independent smFRET studies presented here show that binding of LEDGF/p75, the longer LEDGF splice variant, lead to a looser, more unwound nucleosome, confirming the previously reported chromatin remodeller role of LEDGF/p75. Analyses performed validated smFRET as an excellent tool to study the LEDGF-nucleosome interaction, the details of which are still poorly understood.

Abdul Rahman Sadiq, Zurich, Switzerland

P14: smFRET insights: How a small-molecule disrupts fungal ribozyme activity

Abdul Rahman Sadiq, Susann Zelger-Paulus, Roland K.O. Sigel

Department of Chemistry, University of Zurich, Zurich, CH-8057, Switzerland

Human pathogenic fungi cause significant mortality, with current antifungals limited by their human-cell toxicity[1]. The self-splicing of group II introns in housekeeping genes is essential for pathogenic yeasts[2]. Targeting these ribozymes promises safer antifungals due to their absence in humans. Intronistat B, a small-molecule inhibitor, targets the active-site of group II introns, inhibiting their splicing[3]. While ribozyme-inhibitor crystal structures provide snapshots of inhibition, they fail to capture the inhibitor’s impact on structural rearrangements during splicing[4]. To address this, we investigated the impact of Intronistat B on the folding and splicing of a group II intron Sc.ai5γ.

To track individual ribozymes in real-time, we fluorescently labeled them and used TIRF (Total Internal Reflection Fluorescence) and confocal smFRET (single-molecule Förster Resonance Energy Transfer) techniques. Interestingly, the result revealed stabilization of ribozyme structural conformations upon the addition of the inhibitor. It suggests the inhibitor halts the folding process by confining the ribozyme to certain structural intermediates critical for splicing. These findings shed light on the inhibitor-induced variation in the conformational dynamics of the ribozyme providing further details to the mechanism of Intronistat B action, aiding in rational development of splicing inhibitors. Additionally, the project validates smFRET techniques as powerful tools for probing RNA-inhibitor interactions, bridging single-molecule biophysics and drug development.


[1]      J. Branco, I. M. Miranda, A. G. Rodrigues, Journal of Fungi, 9, 80 (2023).

[2]      J. Nosek, M. Novotna, Z. Hlavatovicova, D. W. Ussery, J. Fajkus, L. Tomaska, Molecular Genetics and Genomics, 272, 173 (2004).

[3]      O. Fedorova, G. E. Jagdmann, R. L. Adams, L. Yuan, M. C. Van Zandt, A. M. Pyle, Nat Chem Biol, 14, 1073 (2018).

[4]      I. Silvestri, J. Manigrasso, A. Andreani, N. Brindani, M. De Vivo, M. Marcia, Nature Communications 15.1: 4980 (2024).

Arjun Sharma, Goettingen, Germany

P15: Polarized FL-SMLM for Sub-Nanometer Single Molecule Colocalization

Arjun Sharma, Oleksii Nevskyi, Ivan Gligonov, Joerg Enderlein

Third Institute of Physics–Biophysics, Georg August University, Göttingen, Germany.

Precise biomolecular structure analysis is a cornerstone of modern biology, as these structures offer insights into the functions, interactions, and mechanisms of biomolecules. Over the last three decades, FRET has been widely adopted for this purpose. However, despite its vast utility, FRET studies require complex data analysis and calibrations and suffer from the generally unknown relative orientation of the fluorescent dyes used. Therefore, the development of angstrom-scale single molecule colocalization methods for non-invasive and precise inter- or intramolecular distance estimation emerges as a pivotal advancement in this quest. In the present work, we explore the potential of fluorescence lifetime single molecule localization microscopy (FL-SMLM) for single molecule colocalization applications, focusing on the inter- or intramolecular distance distributions in biomolecular structures with sub-nanometer spatial accuracy. Fluorescence lifetime adds another dimension to the fluorescence intensity and color acquired by conventional fluorescence microscopy, allowing multiplexing of fluorescent labels even with similar spectral properties. Combined with polarization filtering, this approach further eliminates the need for fluorescence blinking or chromatic correction for single molecule colocalization while achieving molecular-scale spatial resolution. This is particularly useful in single molecule colocalization under cryogenic conditions, opening new avenues for understanding the molecular structures of otherwise highly dynamic molecules.

Evangelos Sisamakis, Berlin, Germany

P17: Adding the fluorescence lifetime dimension to Single-Molecule Localization Microscopy with the confocal microscope Luminosa

Evangelos Sisamakis1, Maria Loidolt-Krüger1, Samrat Basak2, Fabio Barachati1, Roman Tsukanov2, Oleksii Nevskyi2, Cecilia Zaza3, Germán Chiarelli3, Guillermo Acuna3, Jörg Enderlein2, Rainer Erdmann1

1PicoQuant, Rudower Chaussee 29, 12489 Berlin
2University of Göttingen, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen
3University of Fribourg, Department of Physics, Ch. Du Musée 3, 1700 Fribourg

Confocal fluorescence microscopy is an essential tool in many research disciplines, particularly in the life sciences. Its axial sectioning capability is particularly useful for imaging thick samples. Additionally, it can be upgraded to detect fluorescence lifetimes, which can facilitate e.g. multiplexing, environmental sensing, or FLIM-FRET imaging. However, all images have a limited spatial resolution due to diffraction.
Single-molecule localization microscopy (SMLM) approaches such as PAINT or STORM enable fluorescence imaging with spatial super-resolution. But they are usually implemented on camera-based widefield microscopes, which do not support photon counting-based lifetime imaging.

The aim of this research was to add fluorescence lifetime contrast to super-resolution imaging and provide confocal sectioning ability. The fluorescence lifetime information should be exploited either for multiplexing, complementary to spectral approaches, or for providing enhanced axial resolution via MIET-SMLM, or for FRET imaging.

To this end, DNA-PAINT and dSTORM image acquisition were implemented on our time-resolved confocal microscope Luminosa.

For PAINT, the acquisition time per image frame needed to match the binding kinetics of the DNA-PAINT imager strands, such that it was significantly smaller than the average binding time. For dSTORM, the acquisition time should be tuned according to the blinking kinetics of the fluorophore.
Furthermore, an autofocus proved necessary for the lengthy acquisition of a sufficient number of frames, and stable temperature to minimize lateral drift.
The resulting confocal FLIM movies were analyzed similarly as for SMLM measurements to obtain a final super-resolved image. Lastly, the photon arrival times of each single-molecule event were retrieved and analyzed to get the lifetime contrast.
For 3D super-rsolution imaging with MIET-PAINT, the lifetime values were converted to axial positions using the MIET lifetime-distance dependency calculated based on the particular fluorophore properties. For FRET-PAINT, the lifetime was used to detect FRET events.
In conclusion, we demonstrated super-resolved FLIM with PAINT and dSTORM, MIET-PAINT to enable 3D super-resolution as well as super-resolved FRET-PAINT. Importantly, these cutting-edge imaging approaches were realized on a commercially available microscope. Luminosa’s combination of stability, imaging speed, sensitivity and precision in lifetime determination facilitates the easy adaptation of state-of-the-art super-resolution imaging methodologies by other research groups.

Evangelos Sismakis, Berlin, Germany

P16: Small SPAD Arrays for Confocal Fluorescence Lifetime Imaging

Evangelos Sismakis1, Max Tillmann1, Johan Hummert1, Felix Koberling1, Tino Roehlicke1, Michael Wahl1, Cyril Saudan2, Harald Homulle2, Ivan Michel Antolovic2, Rainer Erdmann1

1PicoQuant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany, www.picoquant.com
2Pi Imaging Technology SA, EPFL Innovation Park, 1015 Lausanne, Switzerland, www.piimaging.com

Confocal microscopy is an essential tool in many academic disciplines due to its intrinsic sectioning capability. It combines naturally with time-resolved single photon detection and time-correlated single photon counting (TCSPC) approaches. This has established it as the leading platform for time-resolved investigation methods such as fluorescence lifetime imaging (FLIM) and fluorescence correlation spectroscopy (FCS). Recently, high-performance SPAD-arrays featuring few tens of pixels have become available. Combining these with suitable multi-channel TCSPC devices opens up new possibilities in confocal time-resolved sensing.
In this work we present the two central hardware building blocks which are incorporated into PicoQuant`s new add-on for our confocal microscope Luminosa: a multi-channel TCSPC device and a cooled high-performance 23-pixel SPAD-array developed jointly with Pi Imaging Technologies. We show how the combination of these devices can bring super-resolution imaging modalities such as image scanning microscopy (ISM) to the realm of lifetime imaging. The main benefit of ISM is an increase in SNR as well as lateral and axial resolution, a gain that is fully compatible with lifetime information for species separation. We discuss how advanced data processing can be applied to FLIM-ISM for additional performance gains.
We see the application of small arrays to super-resolution imaging as just one example how this technology can shape the future of confocal time-resolved microscopy. Many more applications are and will potentially be discovered in the coming years as the hardware becomes more readily available.

Jan Sykora, Prague 8, Czech Republic

P18: Modified graphene-based surfaces for the preparation of the cushioned lipid bilayers and their utilization in the biomembrane research

Jan Sykora, Daniela Blanco Campoy, Huseyin Evci, Martin Kalbac, Oleksandr Volochanskyi, Martin Hof, Radek Sachl, Nestor Mora

J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Prague, Czech Republic, jan.sykora@jh-inst.cas.cz, https://www.jh-inst.cas.cz/

Classical fluorescence microscopy is a widely used technique in biological research. However, it inherently suffers from limited spatial resolution, with lateral resolution in the order of hundreds of nanometers and axial resolution of several microns. Recent advancements in novel techniques have achieved nanometric resolution in the lateral dimension. Despite this progress, there remains a high demand for robust methods to achieve nanometer-scale axial resolution. One of the most promising approaches to address this need is Graphene Induced Energy Transfer (GIET).1 GIET relies on the distance-dependent quenching of fluorescence by an atomically thin graphene sheet. Since GIET can operate up to approximately 30 nm, it allows for detailed resolution of lipid bilayers, which are about 5 nm thick.

In this study, we aim to fabricate novel graphene-based supports suitable for GIET. Specifically, graphene deposited on a glass support is cushioned with Pyrene-PEG polymer. Pyrene promotes interaction with graphene, while PEG minimizes the effect of graphene on bilayer behavior. Our experiments focused on forming supported lipid bilayers (SLBs) containing negatively charged lipids on these substrates. The properties of the SLBs were monitored using time-resolved fluorescence microscopy and fluorescence correlation spectroscopy (FCS).

 

Support from Grant 22-25953S from the Czech Science Foundation is greatly acknowledged.


[1] A. Ghosh, A. Sharma., A.I..Chizhik, S. Isbaner, D. Ruhlandt, R. Tsukanov, I. Gregor, N. Karedla, J. Enderlein, Nat. Photonics 13 (2019), 860

Kevin Thommes, Berlin, Germany

P19: Direct interfacing of single organic molecules with an optical nanofiber

Kevin Thommes1, Katja Höflich1,2, Sofia Pazzagli3, Arno Rauschenbeutel3

1Ferdinand-Braun-Institut (FBH), 12489 Berlin, Germany
2Helmholtz-Zentrum Berlin fuer Materialien und Energie, 14109 Berlin, Germany
3Department of Physics, Humboldt-Universitaet zu Berlin, 12489 Berlin, Germany

In quantum technologies, organic molecules have emerged as promising candidates for solid state-
based quantum emitters. Owing to their wide range of emission wavelengths, photostability, defined 
transition dipole moments, and strong zero-phonon lines, organic molecules can be used as bright and 
versatile single photon sources. Single-photon characteristics have been observed for different 
molecules, such as dibenzoterrylene (DBT), even at room temperature [1].  
For the integration of these photon sources into quantum photonic devices, efficient optical interfaces 
are crucial. A considerable overlap of the molecule’s emission pattern with a propagating light field 
can be achieved using optical nanofibers. These subwavelength-diameter waveguides provide a 
pronounced evanescent field component of the guided light [2]. 
We fabricate self-assembled organic nanocrystals (NCs) of anthracene doped with single DBT 
molecules (DBT:Ac) or a cluster of DBT. The DBT:Ac NCs are then suspended in polyvinyl alcohol (PVA) 
for protection against oxidation and spin-coated onto a magnesium fluoride (MgF2) substrate.  A home-
built epi-fluorescence scanning confocal microscope is used to determine the position of the NCs on 
the substrate and to optically characterize their fluorescence signal. A nanofiber mounted on a 
nanopositioning stage can then be placed with respect to the NCs. In this configuration, we can excite 
and collect the fluorescence emission either through the nanofiber or through the microscope. This 
allows decoupling of the excitation and detection path or a fully fiber-based approach without 
additional optical access. Our approach provides a robust and versatile platform for a range of photonic 
quantum applications [3].


[1] S. Pazzagli, P. Lombardi, D. Martella, M. Colautti, B. Tiribilli, F. S. Cataliotti, and C. Toninelli, ACS Nano, 12, 4295−4303 (2018) 
[2] S. M. Skoff, D. Papencordt, H. Schauffert, B. C. Bayer, and A. Rauschenbeutel, Phys. Rev. A, 97, 043839 (2018) 
[3] C. Toninelli, I. Gerhardt, A. S. Clark, A. Reserbat-Plantey, S. Götzinger, Z. Ristanović, M. Colautti, P. Lombardi, K. D. Major, I. Deperasińska, W. H. Pernice, F. H. L. Koppens, B. Kozankiewicz, A. Gourdon, V. Sandoghdar, and M. Orrit, Nat. Mater., 20, 1615-1628 (2021)

Fabian Zundel, Basel, Switzerland

P20: New ways to study life at the nanoscale: the NEOtrap, DyeCycling, & more.

Fabian Zundel, Camila Förster, David Fuentenebro Navas, Srijayee Ghosh, Wenxian Tang, Benjamin Vermeer, Sonja Schmid

Department of Chemistry, University of Basel, Mattenstrasse 22, BPR-1096, 4058 Basel, Switzerland

Proteins are the molecular makers in our body. Researchers successfully identified a vast proteome, a dense web of metabolic interactions, and many thousands of static 3D structures. But the essential dynamic processes causing protein function are still challenging to detect – yet they are the key to the energetics controlling life at the nanoscale. In our group we focus on acquiring time-resolved information to reveal the nano-dynamics of biomolecular systems, such as cancer-assisting chaperone and kinase proteins, and CRISPR-associated proteins. To approach this matter, we develop new electrical and optical single-molecule methods based on nanopores [1,2] and FRET [3,4,5]. The NEOtrap [2] can trap and electrically sense single proteins using nanopores, and with DyeCycling [5], we aim to break the photobleaching limit of smFRET. Most recently, we reported the label-free counting and identification of single secondary messenger molecules produced by type III CRISPR/Cas, viz. cyclic oligo-adenylates [1]. They allosterically activate downstream CARF proteins which act as non-specific ribonucleases in prokaryotic immune systems causing collateral damage by attacking invading but also host RNA [6]. We aim to elucidate this potentially deadly function using smFRET, to directly observe how the underlying conformational dynamics regulate this process allosterically.


[1] Fuentenebro, et al., Schmid ACS Nano 18, 26, 16505–16515 (2024).

[2] Wen, Bertosin, Shi, Dekker, Schmid Nano Letters 23, 3, 788–794 (2022).

[3] Ha, Fei, Schmid et al. Nat Rev Meth Primer 4, 21 (2024)

[4] Götz, et al., Schmid Nature Communications 13, 5402 (2022)

[5] Vermeer, Schmid Nano Research 15, 9818–9830 (2022)

[6] Garcia-Doval, et al. Jinek Nature Communications 11, 1596 (2020)

Abstract guidelines

  • Abstracts can only be submitted along with a registration for the workshop.
  • Abstracts must be submitted in English and be no longer than 200 words (body text) with no graphics.
  • Post deadline abstracts may be considered for poster presentations only (not for oral presentations) and are subject to availability.
  • Abstracts will be made available to workshop participants through the online program overview and the abstract book. If you do not want to have your abstract displayed in the online program overview, please please indicate so during the registration process.
  • Notification on acceptance of abstracts will occur in September 2024.

Workshop fees

  until July 24, 2024      July 25 until September 20, 2024
Academic/University 390 € 440 €
Industry and Private Sector       750 € 950 €

Besides full workshop attendance, the fee includes coffee breaks, a reception with food and drinks, and two lunches. Attendees will be responsible for their own travel, lodging, and additional meals.

Financial support

PicoQuant has a fee waiver program for a small number of participants from universities or academic sector. Accommodation, travel, and personal expenses still need to be paid by the participants themselves. The selection of sponsored people is completely the sole decision of PicoQuant and there is no right or guarantee to receive a fee waiver.

To apply for a fee waiver, please send us your application:

  • a letter of application and
  • a formal letter of recommendation from your department/institute

Deadline for a fee waiver application is July 12, 2024.
Please note that only one person per research group can be considered for a fee waiver.

 

Registration

Registration is closed.

Workshop location

The workshop will be held in the science and technology park of Berlin-Adlershof, located in the south-eastern part of Berlin, not far from the BER Airport.

Venue:
Max-Born-Saal
Carl-Scheele-Straße 6 / Max-Born-Straße
12489 Berlin

Local area map showing the symposium location (red marker)

Accommodation

We have negotiated special rates for a limited number of rooms located close to the workshop location. The number of rooms as well as booking time are limited and we therefore advise to reserve your room as soon as possible.

Hotels within walking distance to the workshop location
 

ADAPT Apartments
Erich-Thilo-Straße 3, 12489 Berlin
Phone: +49-30-678-929-80
Fax: +49-30-678-929-82
Website of the apartment house
info@adaptberlin.de

Room prices per night
  • single room: 115,50 € (excl. breakfast)

Breakfast is available at the hotel‘s catering partners in walking distance. It can be booked directly through the hotel.

Wireless LAN is included in the room price.

ADAPT Apartments Berlin-Adlershof

Booking code: "PicoQuant Workshop 2024"

Please book your room via e-mail or phone using the booking code.

The rooms are bookable at this rate until August 26, 2024 on a first come, first served basis. We cannot guarantee reservations at these prices or any reservations at all after this date.


Airporthotel Berlin-Adlershof
Rudower Chaussee 14, 12489 Berlin
Website of the hotel
info@aha-hotel.de

Room prices per night
  • Single room: 129€ per night including breakfast
  • Double room: 159€ per night including breakfast

breakfast is included in the room price

Airporthotel Berlin-Adlershof

Booking code: "PicoQuant Workshop 2024"

Please book your room by e-mail, phone or fax using the booking code.

The rooms are bookable at this rate until September 9, 2024 on a first come, first served basis. We cannot guarantee reservations at these prices or any reservations at all after this date.

 

Terms and Conditions

Payment and Cancellations

  • After online registration, you will receive an email notification including a PDF file that includes information on the payment procedure.
  • All payments have to be received within 14 days after date of registration.
  • We will send an email confirming your participation once we have received your payment. If payment is overdue, your registration will not be processed and will be considered invalid.
  • A payment receipt will be included in our email confirmation of participation.
  • Cancellation of registration must be submitted in writing or via email and is valid only with acknowledgment of receipt by PicoQuant GmbH. A refund of registration fees is dependent on the notice given:
    • For cancellations made until September 20, 2024, 75 % of the received registration fee will be reimbursed. In case of cancellations after September 20, 2024, 25 % of the registration fee will be reimbursed.
    • It is possible to name and send a substitute participant.
  • No visa letters will be issued until payment of the registration fee is received and confirmed.

General

  • Schedule and content of this event are subject to change without notice.
  • PicoQuant records photographs and video material of participants at the events. By registering for a PicoQuant event, you agree that we may include images of yourself (either as a full image or in parts) for promotional purposes in various publications (press releases, promotional activities, event website, etc.). This material may also appear on our internet web page or on related social media pages. If you do not want us to use pictures in which you appear, please inform us in written form until the end of the workshop.
  • We may also share personal information of event attendees (e.g. in the book of abstracts or in a contact list) with the other persons attending the same event to enable attendees to contact each other prior to, during or after the event for networking purposes. 

Cancellation of registration by PicoQuant due to force majeure

Any circumstances beyond the reasonable control of PicoQuant, including but not limited to acts of nature, fire, severe thunderstorm, earthquakes, volcanic eruptions, terror, threats, pandemics, local or international health crises, security/safety risks or flooding shall constitute “force majeure”. If the force majeure is affecting a PicoQuant event, PicoQuant will notify the participants of such event without undue delay.

When PicoQuant is subject to force majeure, it shall be released from the performance of its obligations relating to any events (partially or wholly) to the extent that such performance is affected by the force majeure.

PicoQuant may take reasonable steps to minimize the consequences of the force majeure on its events and is entitled to reschedule or shorten (in all cases partially or wholly) an event and any performance related to such event. 

For termination of contract concerning an event between PicoQuant and the participant due to force majeure, this shall be without any liability for either party, except in so far as has accrued prior to the date on which the termination of the contract takes effect.

Each party to the contract concerning the event (PicoQuant and the participant) shall itself be responsible for all direct and indirect financial consequences affecting it as a result of or in connection with the force majeure. The occurrence of force majeure shall not entitle either party to any additional payment or compensation.

Code of conduct

The open exchange of ideas and freedom of thought and expression across different fields of research are central to the aims and goals of the Single Molecule Workshop. These require an environment that recognizes the inherent worth of every person and group, that fosters dignity, understanding, mutual respect, and embraces diversity. For these reasons, the Single Molecule Wokrshop organizers are committed to providing a harassment-free course experience.

If you experience harassment or discriminatory behavior at the Single Molecule Workshop, we encourage you to reach out to us for help.

Participants who violate this code may be sanctioned and/or expelled from the event, at the discretion of the organizers. Serious incidents may be referred to the Single Molecule Workshop organizers for further possible action.

If you witness harassment or discriminatory behavior, please consider intervening.

Rights releases

To encourage open communication, each member of a PicoQuant event agrees that any information presented at a PicoQuant event (workshop, course, symposium,etc.) , whether in a formal talk, poster session, or discussion, is a private communication from the individual making the contribution and is presented with the restriction that such information is not for public use.  

Prior to quoting or publishing any such information presented at a conference in any publication, written or electronic, written approval of the contributing member must first be obtained.  The audio or video recording of lectures by any means, the photography of slide or poster material, and printed or electronic quotes from papers, presentations and discussion at a conference without written consent of the contributing member is prohibited.  Scientific publications are not to be prepared as emanating from the conferences.  Authors are requested to omit references to the conferences in any publication, written or electronic.  These restrictions apply to each member of a conference and are intended to cover social networks, blogs, tweets or any other publication, distribution, communication or sharing of information presented or discussed at the conference. 

Guests are not permitted to attend the conference lectures, or poster sessions.  Each member of a conference acknowledges and agrees to these restrictions when registration is accepted and as a condition of being permitted to attend a conference. 

Although PicoQuant staff will take reasonable steps to enforce the restrictions against recording and photographing conference presentations, each member of a conference assumes sole responsibility for the protection and preservation of any intellectual property rights in such member's contributions to a conference.

 

Archive

The workshop on "Single Molecule Spectroscopy and Ultra Sensitive Analysis in the Life Sciences" is an annual event since 1995. To get an impression of our Single Molecule Workshops have a look at the video below.

For a summary of each year's event, please select the year from the list below.

 

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