Bioelectronic In Vitro Cell Membrane Models for Investigating Intestinal Host-Pathogen Interactions

The early stage of pathogen-related diseases often depend on the initial interaction between the pathogen, or it’s secretions, and the host cell membrane. Interfacing cells with electronics allows for quantitative real time monitoring of barrier integrity. Organic electronics coupled with electrochemical impedance spectroscopy (EIS) are used to probe host-pathogen interactions directly with enterocyte plasma membranes using native supported lipid bilayers which are representative of apical and basolateral surfaces of the intestinal epithelium.<br/>PEDOT:PSS is used in both microfabricated planar electrode arrays which can support the formation of supported lipid bilayers. The Caco-2 adenocarcinoma cell line is used to develop a model that reflects in vivo conditions. Cells are differentiated and polarised for 21 days and chemical vesiculation induced to extracted small membrane vesicle biopsies of the apical and basolateral surfaces before being used to form supported lipid bilayers. Fluorescence microscopy is employed to confirm bilayer fluidity with fluorescence recovery after photobleaching (FRAP). EIS is used to determine the impedance of the bilayer across frequencies and models are fit to the data to extract resistance and capacitance values. The ADAM10-receptor mediated effects of <i>Staphylococcus aureus</i> alpha hemolysin toxin is demonstrated and found to be highly dependent on the epithelial membrane surface it encounters. The presence on the receptor in the apical bilayer potentiates the effect of alpha hemolysin leading to a pronounced decrease in membrane resistance compared to the basolateral bilayer.<br/>Organic bioelectronics are used to monitor bilayer and barrier impairment caused by pathogens and their secretions. EIS coupled with conventional biological techniques can be used help elucidate pathogen invasion mechanisms and aid discovery of potential therapeutics.