Flow-based amperometric detection of dopamine in an immobilized cell reactor

A protocol is described for immobilizing PC 12 cells on to the lumen of fused silica microbore tubing having an inside diameter of 250 microm and coated with a thin layer of poly-L-lysine. Optimization studies of the immobilization procedure indicated that a 50 microg ml(-1) solution of poly-L-lysine was the best material for cell adhesion to the fused silica tubing. In addition, it was found that the cells become attached to the poly-L-lysine in approximately 2 h, after which they could be maintained inside of the tubing for a period up to 5 days. Importantly, the immobilized cells ability to release neurotransmitters was evident by measuring the Ca(2+)-induced release of dopamine with an in column amperometric detection scheme involving a Nafion modified platinum ultramicroelectrode.