Article
Chemistry, Physical
Anthony V. Sica, Ash Sueh Hua, Helen H. Lin, Ellen M. Sletten, Timothy L. Atallah, Justin R. Caram
Summary: We demonstrate a method called Spectrally selective Time-resolved Emission through Fourier-filtering (STEF) for separating and resolving the dynamics of multiple emitters without using conventional filters. Our approach utilizes a fixed path-length imbalanced Mach-Zehnder interferometer to interfere and cancel (or enhance) specific spectral signatures corresponding to one emissive species. We show the range and utility of STEF by performing various procedures, including filtering laser scatter, separating fluorescence lifetimes, and resolving overlapping fluorescent stains.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Miyabi Imai-Imada, Hiroshi Imada, Kuniyuki Miwa, Yusuke Tanaka, Kensuke Kimura, Inhae Zoh, Rafael B. Jaculbia, Hiroko Yoshino, Atsuya Muranaka, Masanobu Uchiyama, Yousoo Kim
Summary: This study combines a scanning tunnelling microscope (STM) with localized plasmon fields driven by a tunable laser to directly visualize the photocurrent channels through the molecular orbitals of a single molecule at atomic-scale resolution. The direction and spatial distribution of the photocurrent were found to be sensitive to the bias voltage, and counter-flowing photocurrent channels were detected even at a voltage where the averaged photocurrent is close to zero. The competition between photoinduced electron transfer (PET) and photoluminescence was also observed, and the relaxation pathway of the excited molecule could be controlled by positioning the STM tip with three-dimensional, atomic precision.
Article
Multidisciplinary Sciences
Patrick Hunter, Alex L. Payne-Dwyer, Michael Shaw, Nathalie Signoret, Mark C. Leake
Summary: The ability of tumors to create a pro-tumorigenic microenvironment is an important area of study in the development of new therapeutics. CCR5, a receptor associated with pro-tumorigenic features, is being considered as a potential target for treatment. Various biophysical methods, such as super-resolution structured illumination microscopy and single molecule partially TIRF-coupled HILO microscopy, can provide valuable insights into the structure and function of onco-immunogenic receptors and other biomolecules.
Article
Chemistry, Physical
Jaladhar Mahato, Sukanya Bhattacharya, Dharmendar K. Sharma, Arindam Chowdhury
Summary: Tracking the movement of fluorescent single-molecule tracers has provided new insights into local structure and dynamics in complex environments, but remains unreliable at molecular length scales. Polarization-resolved SMT can reveal authentic pauses within single-molecule trajectories, highlighting the various situations tracers may encounter during transport.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Biochemistry & Molecular Biology
Boris I. Godoy, Nicholas A. Vickers, Sean B. Andersson
Summary: Single Particle Tracking (SPT) is a powerful method for studying biomolecular dynamics in living cells, revealing trajectories of individual particles and motion model parameters. However, existing algorithms assume constant parameters, while this study proposes an estimation algorithm to determine time-varying parameters in systems that switch between different linear models of motion.
Article
Chemistry, Multidisciplinary
Xiaochen Tan, Kevin Welsher
Summary: A new method is introduced to track individual nanoparticles in real-time and measure their protein coronas, revealing that the number of proteins in the dynamic in situ protein corona is twice that of the ex situ measured hard protein corona.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
D. Weckbecker, P. B. Coto, M. Thoss
Summary: This study investigates the potential of proton transfer reactions as a fundamental mechanism to realize a nanoscale molecular transistor. By controlling the location of protons in the molecular bridge and applying an electrostatic gate field, specific conductance states can be selected in molecule-graphene nanojunctions, allowing the current in the junction to be switched on and off like in a field-effect transistor. The underlying mechanism is analyzed in detail.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Biology
Ashwin Balakrishnan, Katherina Hemmen, Susobhan Choudhury, Jan-Hagen Krohn, Kerstin Jansen, Mike Friedrich, Gerti Beliu, Markus Sauer, Martin J. Lohse, Katrin G. Heinze
Summary: The study explores the mobility of the beta 2-adrenergic receptor over a wide temporal range, from nanoseconds to seconds, using various fluorescence spectroscopy techniques. It reveals both translational and rotational mobility, which were previously hidden or overlooked, providing a comprehensive understanding of the receptor's dynamics.
COMMUNICATIONS BIOLOGY
(2022)
Article
Optics
Raymundo Moya, Toru Kondo, Audrey C. Norris, Gabriela S. Schlau-Cohen
Summary: Single-molecule spectroscopy is widely used to study heterogeneity in behaviors on different timescales, with the recent emergence of single-molecule pump-probe spectroscopy for detecting heterogeneity on femtosecond and picosecond timescales. By developing a tunable apparatus, a bimodal distribution of energetic relaxation time constants was found for the fluorescent dye Atto647N, indicating dominance of specific processes within individual molecules and low heterogeneity. This spectrally-tunable single-molecule pump-probe spectroscopy has the potential to investigate heterogeneity in various biological and material systems.
Article
Chemistry, Multidisciplinary
Mingyue Cui, Peiling Dai, Jiali Ding, Manjing Li, Rong Sun, Xin Jiang, Menglin Wu, Xueke Pang, Mingzhu Liu, Qiang Zhao, Bin Song, Yao He
Summary: This article introduces a probe with ultralong phosphorescence lifetime for millisecond-range time-resolved bioimaging, which demonstrates high signal-to-background ratio in imaging live cells and deep tumor tissue in mice.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Lukas Whaley-Mayda, Abhirup Guha, Samuel B. Penwell, Andrei Tokmakoff
Summary: The combination of infrared-vibrational absorption and fluorescent electronic transition techniques in FEIR spectroscopy enables single-molecule sensitivity in solution, allowing for measurement of vibrational spectra and relaxation processes. Introduction of FEIR correlation spectroscopy demonstrates the potential for single-molecule sensitivity in vibrational investigations in solution or condensed phase.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Biochemistry & Molecular Biology
Tatiana R. Simonyan, Elena A. Protasova, Anastasia Mamontova, Aleksander M. Shakhov, Konstantin A. Lukyanov, Eugene G. Maksimov, Alexey M. Bogdanov
Summary: The study demonstrates that a green-fluorescence-protein-based emitter has high sensitivity in alkaline pH range, enabling accurate measurement of mitochondrial pH in live cells.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Physical
Andreas Christ, Patrick Haertl, Manuel Seitz, Tobias Edelmann, Matthias Bode, Jacek Waluk, Markus Leisegang
Summary: We reveal the anisotropic coupling of two distinct vibrational modes to the Cu(110) surface using the molecular nanoprobe technique. The N-H bending mode exhibits maxima perpendicular to the rows of the substrate, while the N-H stretching mode displays maxima along the rows. The anisotropy inversion between these two modes is observed in porphycene adsorbed on Cu(110).
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Review
Biochemistry & Molecular Biology
Rebeca Bocanegra, Ismael G. A. Plaza, Carlos R. Pulido, Borja Ibarra
Summary: The study reveals that the replisome machinery is stochastic, versatile, and highly dynamic, with transient protein-protein and protein-DNA interactions playing a key role in robust DNA replication.
COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL
(2021)
Article
Biochemistry & Molecular Biology
Lukasz Saletnik, Wojciech Szczesny, Jakub Szmytkowski, Jacek J. J. Fisz
Summary: This study systematically investigates the fluorescence spectra of collagen isolated from bovine Achilles tendon under steady-state and time-resolved conditions. The shape and position of the measured fluorescence spectra of collagen strongly depend on the excitation and emission wavelengths, indicating the presence of unidentified collagen cross-links. Time-resolved fluorescence studies suggest energy transfer processes between amino acids and collagen cross-links, as well as between cross-links themselves.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Multidisciplinary Sciences
Kirill Vasilev, Benjamin Doppagne, Tomas Neuman, Anna Roslawska, Herve Bulou, Alex Boeglin, Fabrice Scheurer, Guillaume Schull
Summary: The authors demonstrate the internal Stark effect by observing spectral shifts in the fluorescence spectrum of a phthalocyanine molecule caused by electrostatic fields generated within the molecule itself. This phenomenon of tuning chromophores' optical properties using electrostatic fields is known as the internal Stark effect (ISE) and plays a crucial role in optimizing complex functions in living organisms. By sequentially removing central protons from a free-base phthalocyanine chromophore with a scanning tunneling microscope, the authors were able to measure the Stark shift in the emission energy caused by the charges confined within the chromophore.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Anna Roslawska, Tomas Neuman, Benjamin Doppagne, Andrei G. Borisov, Michelangelo Romeo, Fabrice Scheurer, Javier Aizpurua, Guillaume Schull
Summary: Experimental and theoretical investigation of the interactions between excited states of a single chromophore and static and dynamic electric fields varying at the atomic scale. The fluorescence maps of the chromophore with intramolecular resolution reveal the static charge redistribution and dynamic charge oscillation associated with the molecular exciton.
Article
Optics
Antton Babaze, Eduardo Ogando, P. Elli Stamatopoulou, Christos Tserkezis, N. Asger Mortensen, Javier Aizpurua, Andrei G. Borisov, Ruben Esteban
Summary: In this study, time-dependent density functional theory (TDDFT) was used to investigate the impact of quantum-mechanical effects on the self-interaction Green's function, which governs the electromagnetic interaction between quantum emitters and plasmonic metallic nanoantennas. The results reveal that quantum effects, such as surface-enabled Landau damping and the spill out of induced charges, strongly influence the nanoantenna-emitter interaction, leading to a redshift and broadening of plasmonic resonances. These effects are not considered in classical theories that assume a local dielectric response of the metals.
Correction
Nanoscience & Nanotechnology
Antton Babaze, Ruben Esteban, Javier Aizpurua, Andrei G. Borisov
Article
Materials Science, Multidisciplinary
Juan A. Ramos-Guivar, R. Soria-Martinez
Summary: This research focuses on simulating Gd, Ni, and Ni-Gd core-shell magnetic nanosystems using VAMPIRE software and the Landau-Lifshitz-Gilbert-Heun approach. Temperature dependent magnetization curves were generated to estimate the Curie temperature. Simulations at different particle diameters revealed critical values where the T-c values deviate from the theoretical bulk values. FCC and HCP structure configurations showed similar behaviors at large particle sizes. The magnetic properties can be tuned by varying the core diameter of the Ni-Gd core-shell nanosystem, and antiferromagnetic coupling plays a significant role in the M-T curves and spin distributions.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Chemistry, Physical
Luis E. Parra Lopez, Anna Roslawska, Fabrice Scheurer, Stephane Berciaud, Guillaume Schull
Summary: This study uses a low-temperature scanning tunnelling microscope to probe the excitonic luminescence of a van der Waals heterostructure consisting of a transition metal dichalcogenide monolayer and a few-layer graphene flake stacked on a Au(111) substrate. The intensity and emission energy of the observed neutral, charged, and localized excitons vary with the nanoscale topography of the heterostructure, explaining the variability of emission properties observed with diffraction-limited approaches. This work paves the way for understanding and controlling optoelectronic phenomena in moire superlattices with atomic-scale resolution.
Article
Physics, Multidisciplinary
Song Jiang, Tomas Neuman, Remi Bretel, Alex Boeglin, Fabrice Scheurer, Eric Le Moal, Guillaume Schull
Summary: A scanning tunneling microscope was used to investigate the fluorescence of a charged molecule (quinacridone) adsorbed on a metallic sample covered with sodium chloride. The fluorescence from both neutral and positively charged species was observed and analyzed using hyperresolved fluorescence microscopy. A many-body model was developed based on the analysis of voltage, current, and spatial dependences of fluorescence and electron transport features. This model reveals that the charge states of quinacridone can vary transiently or permanently depending on the voltage and substrate properties.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Song Jiang, Tomas Neuman, Alex Boeglin, Fabrice Scheurer, Guillaume Schull
Summary: In this study, the intrinsic optoelectronic properties of graphene nanoribbons (GNRs) were explored using a scanning tunneling microscope-based method. By transferring the GNRs onto a partially insulating surface, luminescence quenching effects were prevented and localized dark excitons associated with the topological end states of the GNRs were observed.
Article
Nanoscience & Nanotechnology
Antton Babaze, Tomas Neuman, Ruben Esteban, Javier Aizpurua, Andrei G. Borisov
Summary: The surface-response formalism (SRF) incorporates quantum surface-response corrections into classical electromagnetic theory via Feibelman parameters, providing a way to study quantum effects in the optical response of metallic nanostructures. However, the current method neglects the nonlocality of the optical response parallel to the metal-dielectric interface, which limits its applicability to systems with extreme field confinement. To address this limitation, a dispersive SRF based on a generalized Feibelman parameter is introduced, which correctly describes the plasmonic response of planar and nonplanar systems with extreme field confinement. This work significantly extends the applicability range of the SRF and contributes to the development of computationally efficient semiclassical descriptions of light-matter interaction that capture quantum effects.
Article
Multidisciplinary Sciences
Lukas A. Jakob, William M. Deacon, Yuan Zhang, Bart de Nijs, Elena Pavlenko, Shu Hu, Cloudy Carnegie, Tomas Neuman, Ruben Esteban, Javier Aizpurua, Jeremy J. Baumberg
Summary: Plasmonic nano- and pico-cavities can enhance optomechanical coupling, leading to the softening of molecular bonds. The observed non-linear behavior in the Raman spectra is consistent with theoretical simulations and experimental results.
NATURE COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Ruben Esteban, Jeremy J. Baumberg, Javier Aizpurua
Summary: This article describes the relationship, theoretical description, and experimental implementation of molecular optomechanics in SERS. Molecular optomechanics provides a new perspective to explain the nonlinear effects and statistical characteristics in the SERS signal. Through plasmonic resonance, SERS can characterize small numbers or even single molecules. This research is of great significance for the development of novel nanoscale optomechanical devices and the realization of quantum technology.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Physics, Multidisciplinary
Dominik M. Juraschek, Tomas Neuman, Prineha Narang
Summary: This paper presents a mechanism by which optically driven chiral phonon modes in rare-earth trihalides generate giant effective magnetic fields acting on the paramagnetic 4f spins. Using CeCl3 as an example, the coherent phonon dynamics in response to an ultrashort terahertz pulse are calculated using a combination of phenomenological modeling and first-principles calculations. It is found that effective magnetic fields of over 100 T can potentially be generated, polarizing the spins for experimentally accessible pulse energies.
PHYSICAL REVIEW RESEARCH
(2022)