Measuring subdiffraction separations between single fluorescent particles is important for biological, nano-, and medical-technology studies. Major challenges include (i) measuring changing molecular separations with high temporal resolution while (ii) using identical fluorescent labels. Here we report a method that measures subdiffraction separations between two identical fluorophores by using a single image of milliseconds exposure time and a standard single-molecule fluorescent imaging setup. The fluorophores do not need to be bleached and the separations can be measured down to 40 nm with nanometer precision. The method is called single-molecule image deconvolution--SMID, and in this article it measures the standard deviation (SD) of Gaussian-approximated combined fluorescent intensity profiles of the two subdiffraction-separated fluorophores. This study enables measurements of (i) subdiffraction dimolecular separations using a single image, lifting the temporal resolution of seconds to milliseconds, while (ii) using identical fluorophores. The single-image nature of this dimer separation study makes it a single-image molecular analysis (SIMA) study.
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http://dx.doi.org/10.1364/OE.18.016628 | DOI Listing |
Genes Dev
February 2024
Laboratory of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany;
B lineage priming by pioneer transcription factor EBF1 requires the function of an intrinsically disordered region (IDR). Here, we examine the role of regularly spaced tyrosines in the IDR as potential determinants of IDR function and activity of EBF1. We found that four Y > A mutations in EBF1 reduced the formation of condensates in vitro and subdiffractive clusters in vivo.
View Article and Find Full Text PDFAnal Chem
October 2023
Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea.
In live cells, the plasma membrane is composed of lipid domains separated by hundreds of nanometers in dynamic equilibrium. Lipid phase separation regulates the trafficking and spatiotemporal organization of membrane molecules that promote signal transduction. However, visualizing domains with adequate spatiotemporal accuracy remains challenging because of their subdiffraction limit size and highly dynamic properties.
View Article and Find Full Text PDFCell Rep Methods
September 2023
Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, 13005 Marseille, France. Electronic address:
Single-molecule localization microscopy (SMLM) can reach sub-50 nm resolution using techniques such as stochastic optical reconstruction microscopy (STORM) or DNA-point accumulation for imaging in nanoscale topography (PAINT). Here we implement two approaches for faster multicolor SMLM by splitting the emitted fluorescence toward two cameras: simultaneous two-color DNA-PAINT (S2C-DNA-PAINT) that images spectrally separated red and far-red imager strands on each camera, and spectral demixing dSTORM (SD-dSTORM) where spectrally close far-red fluorophores appear on both cameras before being identified by demixing. Using S2C-DNA-PAINT as a reference for low crosstalk, we evaluate SD-dSTORM crosstalk using three types of samples: DNA origami nanorulers of different sizes, single-target labeled cells, or cells labeled for multiple targets.
View Article and Find Full Text PDFNat Commun
July 2023
Département de génie physique, Polytechnique Montréal, Montréal, Québec, H3C 3A7, Canada.
The hyperbolic dispersion relation of phonon-polaritons (PhPols) in anisotropic van der Waals materials provides high-momentum states, directional propagation, subdiffractional confinement, large optical density of states, and enhanced light-matter interactions. In this work, we use Raman spectroscopy in the convenient backscattering configuration to probe PhPol in GaSe, a 2D material presenting two hyperbolic regions separated by a double reststrahlen band. By varying the incidence angle, dispersion relations are revealed for samples with thicknesses between 200 and 750 nm.
View Article and Find Full Text PDFChem Biomed Imaging
April 2023
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
The development and use of interferometric variable-polarization Fourier transform nonlinear optical (vpFT-NLO) imaging to distinguish colloidal nanoparticles colocated within the optical diffraction limit is described. Using a collinear train of phase-stabilized pulse pairs with orthogonal electric field vectors, the polarization of nonlinear excitation fields are controllably modulated between linear, circular, and various elliptical states. Polarization modulation is achieved by precise control over the time delay separating the orthogonal pulse pairs to within hundreds of attoseconds.
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