%0 Journal Article
%A Chambers, Joseph E.
%A Kubánková, Markéta
%A Huber, Roland G.
%A López Duarte, Ismael
%A Avezov, Edward
%A Bond, Peter J.
%A Marciniak, Stefan J.
%A Kuimova, Marina K.
%T An Optical Technique for Mapping Microviscosity Dynamics in Cellular Organelles
%D 2018
%@ 1936-0851
%@ 1936-086X
%U https://hdl.handle.net/20.500.14352/115607
%X Microscopic viscosity (microviscosity) is a key determinant of diffusion in the cell and defines the rate of biological processes occurring at the nanoscale, including enzyme-driven metabolism and protein folding. Here we establish a rotor-based organelle viscosity imaging (ROVI) methodology that enables real-time quantitative mapping of cell microviscosity. This approach uses environment-sensitive dyes termed molecular rotors, covalently linked to genetically encoded probes to provide compartment-specific microviscosity measurements via fluorescence lifetime imaging. ROVI visualized spatial and temporal dynamics of microviscosity with suborganellar resolution, reporting on a microviscosity difference of nearly an order of magnitude between subcellular compartments. In the mitochondrial matrix, ROVI revealed several striking findings: a broad heterogeneity of microviscosity among individual mitochondria, unparalleled resilience to osmotic stress, and real-time changes in microviscosity during mitochondrial depolarization. These findings demonstrate the use of ROVI to explore the biophysical mechanisms underlying cell biological processes.
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