- 标题
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Advanced fluorescence microscopy techniques for the life sciences
摘要： The development of super-resolved fluorescence microscopy, for which the Nobel Prize was awarded in 2014, has been a topic of interest to physicists and biologists alike. It is inevitable that numerous questions in biomedical research cannot be answered by means other than direct observation. In this review, advances to fluorescence microscopy are covered in a widely accessible fashion to facilitate its use in decisions related to its acquisition and utilization in biomedical research.
关键词： Nobel Prize,direct observation,fluorescence microscopy,super-resolution,biomedical research
更新于2025-09-09 09:28:46
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Photochemically Active Dyes for Super-Resolution Microscopy
摘要： The development of super-resolved optical microscopies has revolutionized the way we visualize cell biology. These techniques strongly rely on the use of photochemically active fluorophores that display changes in their photophysical properties upon irradiation with light. Many reversible and irreversible photochemical transformations have been explored for this purpose, and different imaging techniques require specific mechanisms of photoconversion. In this review, we provide an overview of the most common strategies used for the development of fluorophores for super-resolution microscopy and give specific examples of state-of-the-art fluorogenic probes. Furthermore, we discuss their main field of application and possible directions for future developments.
关键词： Live-cell imaging,Photoswitchable,Super-resolution microscopy,Fluorescent probes,Photoactivatable
更新于2025-09-09 09:28:46
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Endogenous Fluorophores Enable Two-Photon Imaging of the Primate Eye
摘要： Noninvasive two-photon imaging of a living mammalian eye can reveal details of molecular processes in the retina and RPE. Retinyl esters and all-trans-retinal condensation products are two types of retinoid fluorophores present in these tissues. We measured the content of these two types of retinoids in monkey and human eyes to validate the potential of two-photon imaging for monitoring retinoid changes in human eyes.
关键词： primate retina,retinoid cycle,two-photon microscopy,rod photoreceptors,cone photoreceptors
更新于2025-09-09 09:28:46
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Protein Phosphorylation || FRET-Based Biosensors: Genetically Encoded Tools to Track Kinase Activity in Living Cells
摘要： Fluorescence microscopy is widely used in biology to localize, to track, or to quantify proteins in single cells. However, following particular events in living cells with good spatio-temporal resolution is much more complex. In this context, Forster resonance energy transfer (FRET) biosensors are tools that have been developed to monitor various events such as dimerization, cleavage, elasticity, or the activation state of a protein. In particular, genetically encoded FRET biosensors are strong tools to study mechanisms of activation and activity of a large panel of kinases in living cells. Their principles are based on a conformational change of a genetically encoded probe that modulates the distance between a pair of fluorescent proteins leading to FRET variations. Recent advances in fluorescence microscopy such as fluorescence lifetime imaging microscopy (FLIM) have made the quantification of FRET efficiency easier. This review aims to address the different kinase biosensors that have been developed, how they allow specific tracking of the activity or activation of a kinase, and to give an overview of the future challenging methods to simultaneously track several biosensors in the same system.
关键词： multiplex,biosensor,fluorescence microscopy,FRET,protein conformation,kinase
更新于2025-09-09 09:28:46
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Phase velocity of drifting spin wave packets in semiconductor two-dimensional electron gas
摘要： We investigated the drift and diffusion dynamics of spin wave packets under spin–orbit effective magnetic fields in two-dimensional electron systems. A simplified model with a spin drift-diffusion equation predicted that the spin phase velocity will change over time from a large negative value to a small positive value. Kerr rotation microscopy revealed the trend we expected for the phase velocity in spin wave packets in a GaAs quantum well. Monte-Carlo simulations agreed with the experiment and showed that the phase velocity can be simply characterized by the spin–orbit parameters and the size ratio between the instantaneous and initial wave packets.
关键词： two-dimensional electron systems,spin wave packets,Kerr rotation microscopy,Monte-Carlo simulations,spin–orbit effective magnetic fields
更新于2025-09-09 09:28:46
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The Use of Index-Matched Beads in Optical Particle Counters
摘要： In this paper, we demonstrate the use of 2-pyridinemethanol (2P) aqueous solutions as a refractive index matching liquid. The high refractive index and low viscosity of 2P-water mixtures enables refractive index matching of beads that cannot be index matched with glycerol-water or sucrose-water solutions, such as silica beads that have the refractive index of bulk fused silica or of polymethylmethacrylate beads. Suspensions of beads in a nearly index-matching liquid are a useful tool to understand the response of particle counting instruments to particles of low optical contrast, such as aggregated protein particles. Data from flow imaging and light obscuration instruments are presented for bead diameters ranging from 6 μm to 69 μm, in a matrix liquid spanning the point of matched refractive index.
关键词： bead,particles,light obscuration,flow imaging,refractive index,flow microscopy
更新于2025-09-09 09:28:46
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European Microscopy Congress 2016: Proceedings || Atom-Resolved STEM Imaging Using a Segmented Detector
摘要： In scanning transmission electron microscopy (STEM), the imaging of atomic columns with a segmented detector has been developed to visualize the local electric field in a crystal. The imaging technique is based on the differential phase contrast (DPC) method, which detects the deflection of the electron beam due to the electric field. The DPC method has been applied to various materials, including semiconductors, metals, and insulators. In this study, we demonstrate the imaging of atomic columns in a SrTiO3 crystal using a segmented detector. The atomic columns are clearly resolved, and the local electric field is visualized. The results show that the DPC method is a powerful tool for studying the electric field in materials at the atomic scale.
关键词： atomic columns,electric field,segmented detector,scanning transmission electron microscopy,differential phase contrast
更新于2025-09-09 09:28:46
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Segmental <sup>13</sup> C-Labeling and Raman Microspectroscopy of α-Synuclein Amyloid Formation
摘要： Mapping conformational changes of a-synuclein (a-syn) from soluble, unstructured monomers to b-sheet-rich aggregates is crucial towards understanding amyloid formation. Raman microspectroscopy is now used to spatially resolve conformational heterogeneity of amyloid aggregates and monitor amyloid formation of segmentally 13C-labeled a-syn in real-time. As the 13C-isotope shifts the amide-I stretching frequency to lower energy, the ligated construct, 12CS87C–140-a-syn, exhibits two distinct bands allowing for simultaneous detection of secondary structural changes in N-terminal 1–86 and C-terminal 87–140 residues. The disordered-to-b-sheet conformational change is first observed for the N-terminal followed by the C-terminal region. Finally, Raman spectroscopic changes occurred prior to Thioflavin T fluorescence enhancement, indicating that the amide-I band is a superior probe of amyloid formation.
关键词： chemical ligation,aggregation,b-sheets,transmission electron microscopy,kinetic intermediates
更新于2025-09-09 09:28:46
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Fluorescent boron Schiff bases dyes for staining silk fibroin: Green synthesis, structural characterization, DFT, and photophysical properties
摘要： Five novel organoboron complexes were synthesized in just 15 min via microware irradiation, by one pot multicomponent reactions between diverse aryl aldehydes with benzoylhydrazide, or 4‐nitrobenzoylhidrazine and diphenyl boronic acid, in a 1:1:1 ratio in benzene. The products were characterized by 1H, 13C, 11B NMR, UV, IR, spectroscopy and high‐resolution mass spectrometry (HRMS). The molecular structure was also determined by single‐crystal X‐ray diffraction for two complexes, which showed the tetra‐coordination of the boron atoms giving rise to distorted tetrahedral molecular geometry with a strong intermolecular C‐H···π interactions. In spite of the low quantum yields exhibited by the series in solution, some complexes stained uniformly the silk fibroins emitting enough fluorescence to allow its characterization by confocal microscopy. Boron as chelate center of the five complexes resulted not to be toxic for B16F10 cells, these compounds are appropriate for their used in medical applications.
关键词： organoboron,silk fibroin,cytotoxicity,confocal microscopy,fluorescent
更新于2025-09-09 09:28:46
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[Methods in Molecular Biology] Systems Chemical Biology Volume 1888 (Methods and Protocols) || Visualizing Bioactive Small Molecules by Alkyne Tagging and Slit-Scanning Raman Microscopy
摘要： An understanding of the intracellular distribution of bioactive small molecules provides insight into their target organelles and biomolecules, and throws light on their molecular mechanisms of action and speci?city. Many studies in this area have employed ?uorescence imaging, using molecules of interest labeled with ?uorescent dyes. However, modi?cation with a bulky ?uorophore may signi?cantly alter the properties, including bioactivity, of small molecules. To address this issue, we have recently developed Raman scattering microscopy of alkyne tags to visualize small molecules in biological systems. The tiny alkyne tag should have a minimal effect on the properties of the tagged molecule, and the unique alkyne vibrational properties allow observation of the Raman signals of the tagged molecules in a wavelength region where there is little interference from Raman signals of endogenous biomolecules. Here we summarize the methodology for Raman imaging of alkyne-tagged bioactive small molecules in living biological systems including the development of slit-scanning Raman microscope, which is useful for fast imaging of alkyne-tagged molecules.
关键词： Slit-scanning Raman microscopy,Raman scattering,Alkyne tag,Small molecules
更新于2025-09-09 09:28:46