Characterization of rat spinal cord neurons cultured in defined media on microelectrode arrays

Previous efforts to utilize mammalian spinal cord neurons as biosensor elem ents have relied on neuronal: glial cocultures maintained in serum-containi ng media. We have examined the feasibility of culturing primary spinal cord neurons in serum-free medium, modified for neuronal longevity, on fabricat ed microelectrode arrays. Embryonic day 15 rat spinal cord cells were plate d on trimethoxysilyl-propyldiethylenetriamine coated microelectrode arrays comprised of gold recording sites passivated with silicon nitride. Immunocy tochemistry was performed to verify the presence of neurons and quantitativ ely assess astrocytes using antibodies against glial fibrillary acidic prot ein on the silicon nitride substrates. Modifications to culture media enabl ed viable neuronal culture to extend from approximately 14 days in vitro (D IV) to 40 DIV on the arrays containing only 1.1 +/- 0.5% (mean +/- SEM) ast rocytes. Extracellular recording revealed tetrodotoxin-sensitive spontaneou s electrical activity from the enriched neuronal culture. Threshold detecti on of extracellular potentials showed an increase in spike rate as a functi on of glutamate concentration with neurotoxicity at elevated levels. This a pproach suggests that functional measures related to biosensor applications , pharmacological screening, or the evaluation of neurological disease mode ls can be implemented in a defined culture system. (C) 1999 Elsevier Scienc e Ireland Ltd. All rights reserved.