An impedimetric biosensor based on PC 12 cells for the monitoring of exogenous agents.

The effect of exogenous agents on the complex impedance of PC 12 cells that were cultured to confluency on 250-mum gold microdot electrodes fabricated within 8-well cell culture biochips was studied. Surface attachment of PC 12 cells to gold microelectrodes was accomplished using cysteamine SAMs covalently derivatized with laminin. The impedimetric response of PC 12 cells that undergo calcium exocytosis in the presence of calcimycin, nifedipine, mannitol and carbachol were identified. Treatment with carbachol induces muscarinic receptor-dependent rises in free cytosolic Ca(2+). Experiments with calcimycin and nifedipine were carried out to clarify the relationship between these two receptor-triggered events. In particular, it is believed to mediate intracellularly the release of Ca(2+) from non-mitochondrial stores. We also examined cellular impedance responsiveness of PC 12 cells in response to phenotypic alteration especially with regard to modulation of ion fluxes using nerve growth factor (NGF), dexamethasone and forskolin. Our results demonstrate that a change in electrophysiological behavior, such as exocytosis of cytosolic Ca(2+) is detectable using impedance spectroscopy, and therefore support the results of impedance fluctuation to be attributed to ion-fluxes.