The development of cell-based biosensors in our laboratory is directed to detecting the effects of several chemical welfare stimulants on the central nervous system. The sensing systems developed are based on pheochromocytoma cells, PC12, that have properties associated with immature neural crest cells that are destined to evolve into adrenal gland chromaffin cells or sympathetic neurons. These neuron-like cells are capable of generating processes or extending projections (axons and dendrites) from their cell body (soma) upon attachments to adhesion substrates (extra cellular matrix proteins). The cessation of proliferation and undergoing of differentiation upon attachment to the adhesion substrate is insignificant. However, in the presence of specific trophic substances, or hormones (i.e. nerve growth factor, NGF), the cells undergo differentiation.

Currently, we use an ECIS 8 Well Electrode Array system for measuring the change in electrical impedance of a small electrode to AC current upon seeding the cells into individual wells. The cell culture chambers sit on an array of gold film electrodes (200 m diameter) that connect to the interrogation unit (instrument applying the current) to each of the 8 wells. The current across bare electrodes encounter low resistance, however, upon the addition of cells, the cells attach and spread upon the gold electrode surface and the current flow is now impeded or restricted and the current must exist within the spaces under and between the cells.

There are many compounds of interest to biological chemical welfare research. We are particularly interested in those molecules that specifically bind to cell surface receptors and affect the functionality of the CNS when the receptor receives these ligands, such as sarin, mustard gas (nerve gases) etc. As a result of binding, changes in a signal transduction pathway are observed due to the enhancement or reduction of the cellular response. Directly, with the use of a time course monitoring of cellular response, we can avoid many potential false positives that occurs with the assays that are concerned with binding. Cell-base sensing provides more reliable information regarding the efficacy of compounds and how the cells are affected over time.