Electrochemical Detection of Signalling Responses in Excitatory and Non Excitatory Cells using Chemoreceptive Neuron MOS Transistors(CVMOS)

Abstract

Transistor based techniques show tremendous potential to detect cellular events with high temporal resolution at the single cell level. We report on a label-free electronic technique using Chemoreceptive MOS transistors (CVMOS) to study the response to stimulation of excitable and non excitable cells. CVMOS charge sensors provide independent gate bias control facilitating capacitive amplification and reference electrode less operation. As a proof of concept, we use this CMOS platform to detect the response of RBL-2H3 mast cells to stimulation mediated through IgE and its high affinity cell surface receptor, FcεRI, using the antigen DNP-BSA on a population of cells. I -V characteristics of the transistor and constant voltage recordings at high temporal resolution suggest changes of extracellular charge and/or capacitance upon stimulation. We observe a shift in the drain current as stimulation is initiated, followed later by current fluctuations that show a time course similar to those of amperometric recordings. The responses are dependent on the presence of extracellular calcium, suggesting that the observed changes may be linked to exocytosis. Unsensitized cells show no detectable response to antigen stimulation. Using adrenal chromaffin cells, we observed rapid current fluctuations in response to stimulation with both ionomycin and high KCl. Experiments are underway to determine whether these responses reflect stimulation action potentials and/or catecholamine release events.