Conductive polymer "molecular wires" increase conductance across artificial cell membranes

Highly intimate contact between an electrode and a living neuron is strongly desired by both basic neuroscientists and engineers seeking to develop more effective neural prostheses. The net resistance between electrode and cell must be decreased in order to improve the quality of recordings and deliver the minimum necessary stimulating current specifically to the target cell. The ideal situation would be to establish chronic intracellular contact, bypassing the resistance of the cell membrane and the surrounding tissue. We present here evidence that regioregular polythiophene conductive polymers increase the electrical conductance of an artificial lipid bilayer that simulates a cell membrane. Our initial data on its behavior suggest that the polymer is freely diffusing within the lipid phase. This implies that these polymers, if tethered to a larger microelectrode, could permit long-term sustainable intracellular stimulation and recording. We therefore believe that this new molecule, when further developed, has the potential to significantly improve the performance of existing chronic electrode systems and possibly to enable new types of biosensors.