Microelectrode Analysis of Cell Plasma Membrane Cholesterol

Abstract

Cholesterol efflux from the cell plasma membrane is known to be increased in cell-line and mouse models of cystic fibrosis. A noninvasive means of characterizing plasma membrane cholesterol efflux at affected tissues is needed to extend the trends found in models of cystic fibrosis to humans suffering from the disease. Microelectrode induced cholesterol efflux from the plasma membrane surface of tissue is proposed as a strategy to demonstrate increased cholesterol efflux for cystic fibrosis in human subjects. Data demonstrating detection of cholesterol efflux from the human buccel mucosa is reported as proof-of-concept for the in vivo diagnostic assay. Cholesterol oxidase modified Pt microelectrodes positioned in contact with the mucosa show increased signal relative to control electrodes indicating observation of cholesterol efflux from mucosa surface cells. Electrochemical detection of cholesterol involves accumulation of enzymatically produced hydrogen peroxide at the electrode surface and periodic oxidative depletion of peroxide in a series of potential step experiments. A nano-electrode array strategy is proposed as a means of increasing signal-to-background of these measurements. Electrodeposition of platinum particles on a carbon microelectrode will be described as an approach to electrode array formation. This work was supported by NIH 1R01EB009481.