Neural prostheses often suffer from undesired chronic inflammatory tissue response.  This can lead to neuronal loss and formation of glial scar tissue, which can serve as a barrier to neural signal transduction.  In situ monitoring of neuro-inflammatory cytokines (Interleukins, TNF-α, MCP-1, PDGF) may improve our understanding of device-induced inflammatory responses.  Furthermore, early detection of the onset and degree of inflammation and the appropriate release of drugs may lead to improved long term performance of such implanted devices.  For this reason, a biosensor based on an aptamer capture probe used in conjunction with non-faradic impedance spectroscopy has been developed.  Aptamers, which are certain kinds of DNA or RNA molecules which can bind a variety of molecules, have overwhelming advantages over antibodies, such as much lower cost and ease of use.  For in situ application, Non-faradic Impedance Spectroscopy (NIS) exhibits extraordinary advantages, because NIS requires no extra reagents or labels.