Real-time electrochemical imaging using an individually addressable multi-channel electrode

We developed a real-time electrochemical imaging method that uses a multipl e enzyme-modified microelectrode. The method will enable the investigation of the functions of biological materials and cells. To test its effectivene ss, we imaged the two-dimensional concentration distribution for hydrogen p eroxide and L-glutamate in a standard solution. The multiple electrode cons ists of an 8 x 8 array of 30 x 30 mum(2) carbon micro electrode. Each elect rode was connected to a 64-channel potentiostat that could apply a potentia l to all electrodes at the same time. The multiple electrode was coated wit h an Os-polyvinylpyridine based polymer (Os-gel) containing horse radish pe roxidase (HRP) to detect hydrogen peroxide, which is a very common product of oxidase enzyme. When measuring glutamate, which is a well-known neurotra nsmitter in the mammalian central nerve system, we modified the electrode w ith a bilayer of Os-gel-HRP and GluOx. The detection limit of our method wa s 1 muM and images of the glutamate concentration-distribution changes indu ced by local injection of glutamate through microcapillary were obtained in real time. (C) 2000 Elsevier Science S.A. All rights reserved.