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Cellular Biophysics

Theoretical and experimental aspects of the effects of electrical fields on membrane processes

Our group's focus is on understanding how time dependent electric fields (e.g., oscillating membrane potentials observed in many systems) influence the behavior of membrane proteins. In particular, we use the theory developed to probe the kinetics and mechanisms by which biological signaling and energy transduction are accomplished. At present, much of our work focuses on fundamental aspects of the statistical mechanics of diffusive and reactive processes in the presence of fluctuating fields and potentials. There is not yet a solid basis for this topic in the physical and mathematical literature, but this is an area that will be extremely important for understanding in detail how membrane proteins accomplish their energy- and signal-transducing roles.


Another interest lies in the kinetics of oscillating and bistable non-linear biochemical reactions

Experimental evidence shows that such reactions are very widespread, yet it is not even known whether such behavior confers a specific evolutionary advantage on an organism, or whether oscillations and bistability are simply unavoidable results of the complex reaction schemes necessary for metabolic control and regulation. We are expanding our interests to include more computationally intensive molecular dynamic simulations of membrane reactions, especially interactions between surfactants and lipid bilayers. Mechanisms of tissue injury in electrical trauma; biophysical control of cellular biosynthetic processes.

The primary efforts of our laboratory are directed at investigating the mechanisms of electrochemical and mechanochemical transduction in cell membranes as they relate to mechanisms of tissue growth and adaptation. We have adopted and refined an in vitro model connective tissue which is used to study the effect of physiologically relevant mechanical stress on cellular biosynthetic proliferative responses. We have further characterized the mechanical properties and kinetics of remodeling of the extracellular matrix by human fibroblasts in this model connective tissue. Our projects now focus on measuring the importance of frequency and amplitude in governing cellular responses. In the future, we will modify the composition of the extracellular matrix so that transductive electromechanical coupling interactions occur in the extracellular matrix. By controlling this, we will be able to determine the importance of matrix composition in modulating cellular responses.

An important aspect of our research relates to the effects of high tension electric fields which can be damaging to cells. We are investigating the effect of supraphysiologic temperatures and supraphysiologic electric fields on the stability of cell membranes. We have established the thresholds for cell membrane breakdown as a result of strong electric field application, and independently, as a result of exposure to supraphysiologic temperatures. We are now investigating mechanisms for stabilizing cell membranes against these effects and possible techniques to reseal membranes following membrane permeabilization. This research is also clinically oriented as it may lead to new therapies for electric shock survivors.

©2010 Chicago Electrical Trauma Research Institute