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Krmpot AJ, Nikolić SN, Oasa S, Papadopoulos DK, Vitali M, Oura M, Mikuni S, Thyberg P, Tisa S, Kinjo M, Nilsson L, Terenius L, Rigler R, Vukojević V. Functional Fluorescence Microscopy Imaging: Quantitative Scanning-Free Confocal Fluorescence Microscopy for the Characterization of Fast Dynamic Processes in Live Cells. Anal Chem 2019; 91:11129-11137. [PMID: 31364842 DOI: 10.1021/acs.analchem.9b01813] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Functional fluorescence microscopy imaging (fFMI), a time-resolved (21 μs/frame) confocal fluorescence microscopy imaging technique without scanning, is developed for quantitative characterization of fast reaction-transport processes in solution and in live cells. The method is based on massively parallel fluorescence correlation spectroscopy (FCS). Simultaneous excitation of fluorescent molecules in multiple spots in the focal plane is achieved using a diffractive optical element (DOE). Fluorescence from the DOE-generated 1024 illuminated spots is detected in a confocal arrangement by a matching matrix detector comprising 32 × 32 single-photon avalanche photodiodes (SPADs). Software for data acquisition and fast auto- and cross-correlation analysis by parallel signal processing using a graphic processing unit (GPU) allows temporal autocorrelation across all pixels in the image frame in 4 s and cross-correlation between first- and second-order neighbor pixels in 45 s. We present here this quantitative, time-resolved imaging method with single-molecule sensitivity and demonstrate its usefulness for mapping in live cell location-specific differences in the concentration and translational diffusion of molecules in different subcellular compartments. In particular, we show that molecules without a specific biological function, e.g., the enhanced green fluorescent protein (eGFP), exhibit uniform diffusion. In contrast, molecules that perform specialized biological functions and bind specifically to their molecular targets show location-specific differences in their concentration and diffusion, exemplified here for two transcription factor molecules, the glucocorticoid receptor (GR) before and after nuclear translocation and the Sex combs reduced (Scr) transcription factor in the salivary gland of Drosophila ex vivo.
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Affiliation(s)
- Aleksandar J Krmpot
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden.,Institute of Physics Belgrade , University of Belgrade , Belgrade 11080 , Serbia
| | - Stanko N Nikolić
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden.,Institute of Physics Belgrade , University of Belgrade , Belgrade 11080 , Serbia
| | - Sho Oasa
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden
| | | | | | - Makoto Oura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science , Hokkaido University , Sapporo , Hokkaido 001-0021 , Japan
| | - Shintaro Mikuni
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science , Hokkaido University , Sapporo , Hokkaido 001-0021 , Japan
| | - Per Thyberg
- Department of Applied Physics , AlbaNova University Center, Royal Institute of Technology , Stockholm 10691 , Sweden
| | - Simone Tisa
- Micro Photon Devices (MPD) , Bolzano 39100 , Italy
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science , Hokkaido University , Sapporo , Hokkaido 001-0021 , Japan
| | - Lennart Nilsson
- Department of Biosciences and Nutrition , Karolinska Institutet , Huddinge 14183 , Sweden
| | - Lars Terenius
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden
| | - Rudolf Rigler
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden.,Department of Medical Biochemistry and Biophysics (MBB) , Karolinska Institutet , Stockholm 17177 , Sweden
| | - Vladana Vukojević
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM) , Karolinska Institutet , Stockholm 17176 , Sweden
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Ingargiola A, Panzeri F, Sarkosh N, Gulinatti A, Rech I, Ghioni M, Weiss S, Michalet X. 8-spot smFRET analysis using two 8-pixel SPAD arrays. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2013; 8590. [PMID: 24386541 DOI: 10.1117/12.2003704] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) techniques are now widely used to address outstanding problems in biology and biophysics. In order to study freely diffusing molecules, current approaches consist in exciting a low concentration (<100 pM) sample with a single confocal spot using one or more lasers and detecting the induced single-molecule fluorescence in one or more spectrally- and/or polarization-distinct channels using single-pixel Single-Photon Avalanche Diodes (SPADs). A large enough number of single-molecule bursts must be accumulated in order to compute FRET efficiencies with sufficient statistics. As a result, the minimum timescale of observable phenomena is set by the minimum acquisition time needed for accurate measurements, typically a few minutes or more, limiting this approach mostly to equilibrium studies. Increasing smFRET analysis throughput would allow studying dynamics with shorter timescales. We recently demonstrated a new multi-spot excitation approach, employing a novel multi-pixel SPAD array, using a simplified dual-view setup in which a single 8-pixel SPAD array was used to collect FRET data from 4 independent spots. In this work we extend our results to 8 spots and use two 8-SPAD arrays to collect donor and acceptor photons and demonstrate the capabilities of this system by studying a series of doubly labeled dsDNA samples with different donor-acceptor distances ranging from low to high FRET efficiencies. Our results show that it is possible to enhance the throughput of smFRET measurements in solution by almost one order of magnitude, opening the way for studies of single-molecule dynamics with fast timescale once larger SPAD arrays become available.
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Affiliation(s)
| | - Francesco Panzeri
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Niusha Sarkosh
- Department of Chemistry & Biochemistry, UCLA, Los Angeles, CA, USA 90095
| | - Angelo Gulinatti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Ivan Rech
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Massimo Ghioni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Shimon Weiss
- Department of Chemistry & Biochemistry, UCLA, Los Angeles, CA, USA 90095
| | - Xavier Michalet
- Department of Chemistry & Biochemistry, UCLA, Los Angeles, CA, USA 90095
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