Photothermal monitoring of respiratory chain redox state in single live cells

摘要

Due to the central role of respiratory chain (RC) in the metabolism of the cell, much attention has been directed at developing efficient techniques for diagnostics of RC at cell level. Proposed method of direct monitoring of the redox state of RC in single live cells is based on photothermal (PT) measurement of photo-induced thermal phenomena in mitochondrial hemoproteins. Thermal output of absorbed light energy depends upon their redox state (oxidized/reduced). PT microscopy method was applied for experimental studies of two in vitro models: (1) solutions of RC component-cytochrome c- and (2) for mice hepatocytes in suspension. Parameters of PT responses obtained from solution and from single cells after their irradiation with laser pulse (532 nm, 8 ns) were found to be different for oxidized and reduced forms for cytochrome c solutions and for KCN and Antimicine A treated cells in comparison to intact ones. This difference may be caused by alteration of the quantum yields of thermal (non-radiative) relaxation for light absorbing molecules-RC components-as they undergo redox state change under influence of RC inhibitors. Obtained results allow to suggest new approach for monitoring of functional activity of RC in single cell through the measurement of PT response at specific wavelengths.