engleski

Adhesion and spreading of a cell at a charged interface

The single cell-electrode interaction is relevant to fundamental biological processes involving cell adhesion, cell fusion, cell activity, and membrane response to environmental stress. We studied kinetics of adhesion and spreading of the algal cell and its plasma membrane vesicle to the charged mercury interface. Adhesion and spreading of a cell at a charged interface cause double layer charge displacement which is measured as a well defined amperometric signal in millisecond time scale. The signal denotes establishment of intimate membrane contact at the interface with subsequent cell spreading, followed by cell breakdown in a few milliseconds. Application of the reaction kinetics model enables calculation of kinetic parameters of the adhesion process from the signal, enabling to decouple and identify temporal evolution of the individual states. We demonstrate validity and pertinence of the reaction kinetics model in the wide range of surface charge densities. Adhesion kinetics of algal cell is slower than its plasma membrane vesicle. The model enables to associate individual states with various features of amperometric signal. At the time of current amplitude, ruptured state predominates and cell contact area is larger than contact area of the plasma membrane vesicle which contributes about one quarter to the cell contact area. These results suggest that the major structural disruption of the cell membrane, collapse of cytoskeleton and leakage of intracellular material could appear close to the time of current amplitude. Further, kinetics of spreading of organic film at the interface to its maximal extent is being considered as the rate determining step, which could be consequence of the attenuated effect of potential at the modified interface, stronger intermolecular interactions and reorganization of molecules in the film. Our findings offer insight into the mechanism of algal cell adhesion and spreading at the charged interfaces

AFM; amperometry; cell adhesion; reaction kinetics mode; plasma membrane vesicles

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