Electrochemical sensor array and its application to real time imaging of a brain slice

An electrochemical sensing system using a planar microelectrode array has been developed to monitor biological molecules with relatively high special and temporal resolutions. This enables us a real time imaging of the biological molecules release from a tissue invasively. In this study, we have established a multichannel hydrogen peroxide (H₂O₂:) sensing system to monitor the real time H₂O₂ distribution in a tissue using a planar sensor array. H₂O₂ has been recognized in association with the pathology of neurological diseases because it is a by-product of a degenerative reaction of reactive oxygen species, one of the major causes of oxidative stress in mammalian cells. The sensor array is based on a 64-channel ITO electrode array of 50×50 um electrodes modified with an enzyme, horseradish peroxidase, and an electron transfer mediator. Then we place a cultured rat hippocampal slice on the array and measure the current at each sensor using a multipotentiostat. When we introduce bicuculline into the solution as a stimulant, in the presence of a catalase inhibitor, we can observe a distinct increase in the H₂O₂ concentration. This real-time H₂O₂ distribution monitoring system will be a powerful tool with which to explore the neuronal cell death mechanism in biological systems.