Temporal Resolution in Electrochemical Imaging on Single PCI 2 Cells Using Amperometry and Voltammetry at Microelectrode Arrays.

Carbon-fiber-microelectrode arrays (MEAs) have been utilized to electrochenilcally image neurochemical secretion from individual pheochromocytoma (PC12) cells. Dopamine release events were elecirochemicaily monitored from seven different locations on single Pci 2 cells using alternately constant-potential amperomehy and fast-scan cyclic voltammetzy (FSCV). Cyclic voltammetry, when compared to amperometry, can provide excellent chemical resolution; however, spatial and temporal resolution are both compromised. The spatial and temporal resolution of these two methods have been quantitatively compared and the differences explained using models of molecular diffusion at the nanogap between the electrode and the cell. A nuinencal simulation of the molecular flux reveals that the diffusion of dopamine molecules and elecirochemical reactions both play important roles in the temporal resolution of elecirochemical imaging. The simulation also reveals that the diffusion and electrode potential cause the differences in signal crosstalk between electrodes when comparing amperometxy and FSCV. [ABSTRACT FROM AUTHOR]