Fabrication and sensing applications of microelectrodes on silicon substrates

The unique properties of microelectrodes have been appreciated by electroch emists for some years, but the development of sensors which use these prope rties, in particular the high diffusion rates near the electrodes, has been slow. We consider first the dimensions which define microelectrodes. Silic on fabrication methods are well able to reach these, but the technology, ou tlined for a simple case of the production of an electrode array, is specia lized. Progress in developing sensors will best be made by collaborations b etween engineering and electrochemistry groups. Examples of sensors and dev ices which utilize microelectrodes are given. Three depend on the high diff usion fluxes which can be established near microelectrodes, and one uses th e fact that microstructures can be made which have features comparable in s ize to living cells. The resulting nonuniform electric fields allow cells t o be manipulated.