An Optical Technique for Mapping Microviscosity Dynamics in Cellular Organelles.

Area of Science:

• Cell biology
• Biophysics
• Biochemistry

Background:

• Cellular microviscosity influences nanoscale biological processes like metabolism and protein folding.
• Understanding intracellular viscosity is crucial for deciphering cellular function.

Purpose of the Study:

• To establish a novel methodology for real-time, quantitative mapping of intracellular microviscosity.
• To investigate the spatial and temporal dynamics of microviscosity within subcellular compartments.

Main Methods:

• Development of rotor-based organelle viscosity imaging (ROVI).
• Utilizing environment-sensitive molecular rotors covalently linked to genetically encoded probes.
• Employing fluorescence lifetime imaging for compartment-specific microviscosity measurements.

Main Results:

• ROVI enabled visualization of microviscosity dynamics with suborganellar resolution.
• Demonstrated significant microviscosity differences (nearly an order of magnitude) between subcellular compartments.
• Observed mitochondrial matrix heterogeneity, osmotic resilience, and real-time viscosity changes during depolarization.

Conclusions:

• ROVI is a powerful tool for quantitative, real-time microviscosity mapping within cells.
• The study revealed novel insights into mitochondrial microviscosity heterogeneity and dynamics.
• ROVI facilitates exploration of biophysical mechanisms governing cellular processes.