Ultramicrobiosensor for the selective detection of glutamate

Carbon fiber microelectrodes, able to detect catecholamine release from single cells, have significantly contributed to our present understanding of the mechanism of secretory neurotransmission. In spite of their obvious advantages, there are only a few amperometric sensors (characterized by appropriate size, sensitivity, and selectivity) able to measure the release of other (not easily oxidizable) neurotransmitters at cellular level. The present work describes the fabrication and characterization of an ultramicrobiosensor for the selective detection of glutamate. ne developed sensor has a size of 2.5 - 15 mu m in diameter, a sensitivity of 0.62 mA mM(-1) cm(-2), and a detection limit of 5 mu M. The excellent selectivity of the sensor (achieved using electrodeposition of Ru, Rh, and poly(m-phenylenediamine)) makes it a promising candidate for monitoring glutamate release at single cell level.