Interacting with biological membranes using organic electronic devices

Abstract: Many physiological processes are reliant on activities in the cell membrane. These activities are of great importance to our well-being since they allow the cells to respond to their environment and communicate with each other to function as tissues and organs. In this thesis the use of organic electronic devices to interface with cell membranes has been explored. Organic electronics are especially suited for the task given their ability to transduce ionic to electronic signals. Four scientific papers are included in the thesis, where organic electronic devices are used together with living cells and supported lipid bilayers (SLB). In the first paper a ferroelectric cell release surface is presented. Release of cells cultured on the surface was induced by a polarization change in the ferroelectric polymer. This non-enzymatic release method was developed primarily for treatment of severe burns.The remaining three papers strive to combine lipid bilayers and the conjugated polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) in biosensors. The target device is an organic electrochemical transistor (OECT) functionalized with a supported lipid bilayer. Several aspects of the integration are explored, including promotion of vesicle fusion onto PEDOT:PSS and optimization of OECT design and biasing conditions for sensing. For SLB formation on PEDOT:PSS two different silica material systems, one PEDOT:PSS/silica composite and one mesoporous silica film, were evaluated with respect to electrical properties and quality of the resulting bilayer. The electrical properties were found to be similar, but the quality of the bilayer was better on the mesoporous silica film.In the last two papers the focus is on optimization of OECTs for sensing purposes. Biasing conditions for operation at high transconductance were identified, as well as design principles for large sensor output in impedance sensing.