1
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Grabenhorst L, Sturzenegger F, Hasler M, Schuler B, Tinnefeld P. Single-Molecule FRET at 10 MHz Count Rates. J Am Chem Soc 2024; 146:3539-3544. [PMID: 38266173 DOI: 10.1021/jacs.3c13757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
A bottleneck in many studies utilizing single-molecule Förster resonance energy transfer is the attainable photon count rate, as it determines the temporal resolution of the experiment. As many biologically relevant processes occur on time scales that are hardly accessible with currently achievable photon count rates, there has been considerable effort to find strategies to increase the stability and brightness of fluorescent dyes. Here, we use DNA nanoantennas to drastically increase the achievable photon count rates and observe fast biomolecular dynamics in the small volume between two plasmonic nanoparticles. As a proof of concept, we observe the coupled folding and binding of two intrinsically disordered proteins, which form transient encounter complexes with lifetimes on the order of 100 μs. To test the limits of our approach, we also investigated the hybridization of a short single-stranded DNA to its complementary counterpart, revealing a transition path time of 17 μs at photon count rates of around 10 MHz, which is an order-of-magnitude improvement compared to the state of the art. Concomitantly, the photostability was increased, enabling many seconds long megahertz fluorescence time traces. Due to the modular nature of the DNA origami method, this platform can be adapted to a broad range of biomolecules, providing a promising approach to study previously unobservable ultrafast biophysical processes.
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Affiliation(s)
- Lennart Grabenhorst
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | | | - Moa Hasler
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
- Department of Physics, University of Zurich, 8057 Zurich, Switzerland
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, 81377 München, Germany
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2
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Lyons A, Zickus V, Álvarez-Mendoza R, Triggiani D, Tamma V, Westerberg N, Tassieri M, Faccio D. Fluorescence lifetime Hong-Ou-Mandel sensing. Nat Commun 2023; 14:8005. [PMID: 38049423 PMCID: PMC10696080 DOI: 10.1038/s41467-023-43868-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/22/2023] [Indexed: 12/06/2023] Open
Abstract
Fluorescence Lifetime Imaging Microscopy in the time domain is typically performed by recording the arrival time of photons either by using electronic time tagging or a gated detector. As such the temporal resolution is limited by the performance of the electronics to 100's of picoseconds. Here, we demonstrate a fluorescence lifetime measurement technique based on photon-bunching statistics with a resolution that is only dependent on the duration of the reference photon or laser pulse, which can readily reach the 1-0.1 picosecond timescale. A range of fluorescent dyes having lifetimes spanning from 1.6 to 7 picoseconds have been here measured with only ~1 s measurement duration. We corroborate the effectiveness of the technique by measuring the Newtonian viscosity of glycerol/water mixtures by means of a molecular rotor having over an order of magnitude variability in lifetime, thus introducing a new method for contact-free nanorheology. Accessing fluorescence lifetime information at such high temporal resolution opens a doorway for a wide range of fluorescent markers to be adopted for studying yet unexplored fast biological processes, as well as fundamental interactions such as lifetime shortening in resonant plasmonic devices.
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Affiliation(s)
- Ashley Lyons
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Vytautas Zickus
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
- Department of Laser Technologies, Center for Physical Sciences and Technology, LT-10257, Vilnius, Lithuania
| | | | - Danilo Triggiani
- School of Mathematics and Physics, University of Portsmouth, Portsmouth, PO1 3QL, UK
| | - Vincenzo Tamma
- School of Mathematics and Physics, University of Portsmouth, Portsmouth, PO1 3QL, UK
- Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX, UK
| | - Niclas Westerberg
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Manlio Tassieri
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Daniele Faccio
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
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3
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Fersch D, Malý P, Rühe J, Lisinetskii V, Hensen M, Würthner F, Brixner T. Single-Molecule Ultrafast Fluorescence-Detected Pump-Probe Microscopy. J Phys Chem Lett 2023:4923-4932. [PMID: 37207316 DOI: 10.1021/acs.jpclett.3c00839] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We introduce fluorescence-detected pump-probe microscopy by combining a wavelength-tunable ultrafast laser with a confocal scanning fluorescence microscope, enabling access to the femtosecond time scale on the micrometer spatial scale. In addition, we obtain spectral information from Fourier transformation over excitation pulse-pair time delays. We demonstrate this new approach on a model system of a terrylene bisimide (TBI) dye embedded in a PMMA matrix and acquire the linear excitation spectrum as well as time-dependent pump-probe spectra simultaneously. We then push the technique toward single TBI molecules and analyze the statistical distribution of their excitation spectra. Furthermore, we demonstrate the ultrafast transient evolution of several individual molecules, highlighting their different behavior in contrast to the ensemble due to their individual local environment. By correlating the linear and nonlinear spectra, we assess the effect of the molecular environment on the excited-state energy.
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Affiliation(s)
- Daniel Fersch
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Pavel Malý
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
| | - Jessica Rühe
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Victor Lisinetskii
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Matthias Hensen
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Frank Würthner
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
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4
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Sarkar A, Kumbhakar M. Inter-molecular Interaction Kinetics: Tale of Photon Anti-bunching and Bunching in Fluorescence Correlation Spectroscopy (FCS). Methods Appl Fluoresc 2022; 10. [PMID: 35817064 DOI: 10.1088/2050-6120/ac804b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/11/2022] [Indexed: 11/12/2022]
Abstract
Molecular interactions are fundamental to any chemical or biological processes, and their rates define the operational sequence and control for any desirable product. Here, we deliberate on a recently developed novel fluorescence spectroscopic method, which combines fluorescence photon anti-bunching, photon bunching, time-correlated single-photon counting (TCSPC), and steady-state fluorescence spectroscopy, to study composite chemical reactions with single molecule sensitivity. The proposed method captures the full picture of the multifaceted quenching kinetics, which involves static quenching by ground state complexation and collisional quenching in the excited state under dynamic exchange of fluorophore in a heterogeneous media, and which cannot be seen by steady-state or lifetime measurements alone. Photon correlation in fluorescence correlation spectroscopy (FCS) provides access to interrogate interaction dynamics from picosecond to seconds, stitching all possible stages of dye-quencher interaction in a micellar media. This is not possible with the limited time window available to conventional ensemble techniques like TCSPC, flash photolysis, transient absorption, stop-flow, etc. The basic premises of such unified global analysis and sanctity of extracted parameters critically depends on the minimum but precise description of reaction scheme, for which careful inspection of ensemble spectroscopy data for photo-physical behaviour is very important. Though in this contribution we discussed and demonstrated the merits of photon antibunching and bunching spectroscopy for dye-quencher interaction in cationic cetyltrimethylammonium bromide (CTAB) micellar solution by photo-induced electron transfer mechanism and the influence of micellar charge and microenvironment on the interaction kinetics, but in principal similar arguments are equally applicable to any other interaction mechanisms which alter fluorescence photon correlations, like Förster resonance energy transfer (FRET), proton transfer, isomerisation, etc.
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Affiliation(s)
- Aranyak Sarkar
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, CFB, C-139, Mumbai, Maharashtra, 400085, INDIA
| | - Manoj Kumbhakar
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, CFB, C-139, Mumbai, 400085, INDIA
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5
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Schröder T, Bange S, Schedlbauer J, Steiner F, Lupton JM, Tinnefeld P, Vogelsang J. How Blinking Affects Photon Correlations in Multichromophoric Nanoparticles. ACS NANO 2021; 15:18037-18047. [PMID: 34735135 DOI: 10.1021/acsnano.1c06649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A single chromophore can only emit a maximum of one single photon per excitation cycle. This limitation results in a phenomenon commonly referred to as photon antibunching (pAB). When multiple chromophores contribute to the fluorescence measured, the degree of pAB has been used as a metric to "count" the number of chromophores. But the fact that chromophores can switch randomly between bright and dark states also impacts pAB and can lead to incorrect chromophore numbers being determined from pAB measurements. By both simulations and experiment, we demonstrate how pAB is affected by independent and collective chromophore blinking, enabling us to formulate universal guidelines for correct interpretation of pAB measurements. We use DNA-origami nanostructures to design multichromophoric model systems that exhibit either independent or collective chromophore blinking. Two approaches are presented that can distinguish experimentally between these two blinking mechanisms. The first one utilizes the different excitation intensity dependence on the blinking mechanisms. The second approach exploits the fact that collective blinking implies energy transfer to a quenching moiety, which is a time-dependent process. In pulsed-excitation experiments, the degree of collective blinking can therefore be altered by time gating the fluorescence photon stream, enabling us to extract the energy-transfer rate to a quencher. The ability to distinguish between different blinking mechanisms is valuable in materials science, such as for multichromophoric nanoparticles like conjugated-polymer chains as well as in biophysics, for example, for quantitative analysis of protein assemblies by counting chromophores.
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Affiliation(s)
- Tim Schröder
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Sebastian Bange
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany
| | - Jakob Schedlbauer
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany
| | - Florian Steiner
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany
| | - Philip Tinnefeld
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany
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6
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Freixas VM, Wilhelm P, Nelson T, Hinderer F, Höger S, Tretiak S, Lupton JM, Fernandez-Alberti S. Excitation Energy Transfer between bodipy Dyes in a Symmetric Molecular Excitonic Seesaw. J Phys Chem A 2021; 125:8404-8416. [PMID: 34542292 DOI: 10.1021/acs.jpca.1c06332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We examine the redistribution of energy between electronic and vibrational degrees of freedom that takes place between a π-conjugated oligomer, a phenylene-butadiynylene, and two identical boron-dipyrromethene (bodipy) end-caps using femtosecond transient absorption spectroscopy, single-molecule spectroscopy, and nonadiabatic excited-state molecular dynamics (NEXMD) modeling techniques. The molecular structure represents an excitonic seesaw in that the excitation energy on the oligomer backbone can migrate to either one end-cap or the other, but not to both. The NEXMD simulations closely reproduce the characteristic time scale for redistribution of electronic and vibrational energy of 2.2 ps and uncover the vibrational modes contributing to the intramolecular relaxation. The calculations indicate that the dihedral angle between the bodipy dye and the oligomer change upon excitation of the oligomer. Single-molecule experiments reveal a difference in photoluminescence lifetime of the bodipy dyes depending on whether they are excited by direct absorption or by redistribution of energy from the backbone. This difference in lifetime may be attributed to the difference in dihedral angle. The simulations also suggest that a strong coupling can occur between the two end-caps, giving rise to a reversible shuttling of excitation energy between them. Strong coupling should lead to a pronounced loss in polarization memory of the fluorescence since the oligomer backbone tends to be slightly distorted and the two bodipy transition dipoles have different orientations. A sensitive single-molecule technique is presented to test for such coupling. However, although redistribution of electronic and vibrational energy between the end-caps can occur, it appears to be unidirectional and irreversible, suggesting that an additional localization mechanism is at play which is, as yet, not fully accounted for in the simulations.
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Affiliation(s)
- Victor M Freixas
- Departamento de Ciencia y Tecnologia, Universidad Nacional de Quilmes/CONICET, B1876BXD Bernal, Argentina
| | - Philipp Wilhelm
- Institut für Angewandte und Experimentelle Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Tammie Nelson
- Theoretical Division and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Florian Hinderer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Sigurd Höger
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Sergei Tretiak
- Theoretical Division and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - John M Lupton
- Institut für Angewandte und Experimentelle Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
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7
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Glembockyte V, Grabenhorst L, Trofymchuk K, Tinnefeld P. DNA Origami Nanoantennas for Fluorescence Enhancement. Acc Chem Res 2021; 54:3338-3348. [PMID: 34435769 DOI: 10.1021/acs.accounts.1c00307] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The possibility to increase fluorescence by plasmonic effects in the near-field of metal nanostructures was recognized more than half a century ago. A major challenge, however, was to use this effect because placing single quantum emitters in the nanoscale plasmonic hotspot remained unsolved for a long time. This not only presents a chemical problem but also requires the nanostructure itself to be coaligned with the polarization of the excitation light. Additional difficulties arise from the complex distance dependence of fluorescence emission: in contrast to other surface-enhanced spectroscopies (such as Raman spectroscopy), the emitter should not be placed as close as possible to the metallic nanostructure but rather needs to be at an optimal distance on the order of a few nanometers to avoid undesired quenching effects.Our group addressed these challenges almost a decade ago by exploiting the unique positioning ability of DNA nanotechnology and reported the first self-assembled DNA origami nanoantennas. This Account summarizes our work spanning from this first proof-of-principle study to recent advances in utilizing DNA origami nanoantennas for single DNA molecule detection on a portable smartphone microscope.We summarize different aspects of DNA origami nanoantennas that are essential for achieving strong fluorescence enhancement and discuss how single-molecule fluorescence studies helped us to gain a better understanding of the interplay between fluorophores and plasmonic hotspots. Practical aspects of preparing the DNA origami nanoantennas and extending their utility are also discussed.Fluorescence enhancement in DNA origami nanoantennas is especially exciting for signal amplification in molecular diagnostic assays or in single-molecule biophysics, which could strongly benefit from higher time resolution. Additionally, biophysics can greatly profit from the ultrasmall effective detection volumes provided by DNA nanoantennas that allow single-molecule detection at drastically elevated concentrations as is required, e.g., in single-molecule DNA sequencing approaches.Finally, we describe our most recent progress in developing DNA NanoAntennas with Cleared HOtSpots (NACHOS) that are fully compatible with biomolecular assays. The developed DNA origami nanoantennas have proven robustness and remain functional after months of storage. As an example, we demonstrated for the first time the single-molecule detection of DNA specific to antibiotic-resistant bacteria on a portable and battery-driven smartphone microscope enabled by DNA origami nanoantennas. These recent developments mark a perfect moment to summarize the principles and the synthesis of DNA origami nanoantennas and give an outlook of new exciting directions toward using different nanomaterials for the construction of nanoantennas as well as for their emerging applications.
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Affiliation(s)
- Viktorija Glembockyte
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Lennart Grabenhorst
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Kateryna Trofymchuk
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
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8
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Hedley GJ, Schröder T, Steiner F, Eder T, Hofmann FJ, Bange S, Laux D, Höger S, Tinnefeld P, Lupton JM, Vogelsang J. Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores. Nat Commun 2021; 12:1327. [PMID: 33637741 PMCID: PMC7910429 DOI: 10.1038/s41467-021-21474-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/27/2021] [Indexed: 11/27/2022] Open
Abstract
The particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.
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Affiliation(s)
| | - Tim Schröder
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, München, Germany
| | - Florian Steiner
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, München, Germany
| | - Theresa Eder
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Regensburg, Germany
| | - Felix J Hofmann
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Regensburg, Germany
| | - Sebastian Bange
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Regensburg, Germany
| | - Dirk Laux
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
| | - Sigurd Höger
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
| | - Philip Tinnefeld
- Department Chemie and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, München, Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Regensburg, Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik and Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg, Regensburg, Germany.
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9
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Liisberg MB, Shakeri Kardar Z, Copp SM, Cerretani C, Vosch T. Single-Molecule Detection of DNA-Stabilized Silver Nanoclusters Emitting at the NIR I/II Border. J Phys Chem Lett 2021; 12:1150-1154. [PMID: 33476515 DOI: 10.1021/acs.jpclett.0c03688] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The near-infrared (NIR) I and II regions are known for having good light transparency of tissue and less scatter compared to the visible region of the electromagnetic spectrum. However, the number of bright fluorophores in these regions is limited. Here we present a detailed spectroscopic characterization of a DNA-stabilized silver nanocluster (DNA-AgNC) that emits at around 960 nm in solution. The DNA-AgNC converts to blue-shifted emitters over time. Embedding these DNA-AgNCs in poly(vinyl alcohol) (PVA) shows that they are bright and photostable enough to be detected at the single-molecule level. Photon antibunching experiments were performed to confirm single emitter behavior. Our findings highlight that the screening and exploration of DNA-AgNCs in the NIR II region might yield promising bright, photostable emitters that could help develop bioimaging applications with unprecedented signal-to-background ratios and single-molecule sensitivity.
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Affiliation(s)
- Mikkel B Liisberg
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Zahra Shakeri Kardar
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | | | - Cecilia Cerretani
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Tom Vosch
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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10
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Maccaferri N, Meuret S, Kornienko N, Jariwala D. Speeding up Nanoscience and Nanotechnology with Ultrafast Plasmonics. NANO LETTERS 2020; 20:5593-5596. [PMID: 32787183 DOI: 10.1021/acs.nanolett.0c02452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface plasmons are collective oscillations of free electrons at the interface between a conducting material and the dielectric environment. These excitations support the formation of strongly enhanced and confined electromagnetic fields. As well, they display fast dynamics lasting tens of femtoseconds and can lead to a strong nonlinear optical response at the nanoscale. Thus, they represent the perfect tool to drive and control fast optical processes, such as ultrafast optical switching, single photon emission, as well as strong coupling interactions to explore and tailor photochemical reactions. In this Virtual Issue, we gather several important papers published in Nano Letters in the past decade reporting studies on the ultrafast dynamics of surface plasmons.
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Affiliation(s)
- Nicolò Maccaferri
- Department of Physics and Materials Science, Université du Luxembourg, 162a avenue de la Faïencerie, L-1511, Luxembourg, Luxembourg
| | - Sophie Meuret
- CEMES, CNRS - UPR8011, Université de Toulouse, 31055 Toulouse, France
| | - Nikolay Kornienko
- Department of Chemistry, Université de Montréal, Roger-Gaudry Building, Montreal, Quebec H3C 3J7, Canada
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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11
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Schedlbauer J, Scherf U, Vogelsang J, Lupton JM. Dynamic Quenching of Triplet Excitons in Single Conjugated-Polymer Chains. J Phys Chem Lett 2020; 11:5192-5198. [PMID: 32506907 DOI: 10.1021/acs.jpclett.0c01308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
By measuring the fluorescence photon statistics of single chains of a conjugated polymer, we determine the lifetime of the metastable dark state, the triplet exciton. The single molecule emits single photons one at a time, giving rise to photon antibunching. These photons appear bunched in time over longer time scales because of excursions to the triplet dark state. Remarkably, this triplet intermittency in the fluorescence is spontaneously suppressed over time scales of seconds, implying that either triplet formation is inhibited or that triplets are selectively quenched without the singlet fluorescence being affected. Such discrete switching in the strength of photon bunching is only seen in highly ordered and rigid chains of a ladder-type conjugated polymer. It does not occur in single dye molecules. We propose that trapped photogenerated charges on the chain selectively quench triplets but not singlets, presumably because the effective diffusion length of triplets is longer along the highly rigid ladder-type backbone.
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Affiliation(s)
- Jakob Schedlbauer
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Ullrich Scherf
- Macromolecular Chemistry Group, Chemistry Department and Wuppertal Center for Smart Materials & Systems CM@S, Bergische Universität Wuppertal, Gauss-Strasse 20, 42097 Wuppertal, Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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