Enzyme, immuno, and microbial sensors have been developed and applied for clinical analysis, the process control and environmental monitoring.
Electrodes have been generally used as a transducer in biosensors, but attention is now focusing on sensors utilizing a semiconductor device as a transducer The use of semiconductor devices or microelectrodes enables the miniaturization of biosensors, consequently allows the measurement using only minute amount of samples and also the integration of several biosensors in one chip. Furthermore, the mass production of these devices and electrodes is also possible, hence the price of biosensors can be reduced. The reduction in price allows the development of disposable type microbiosensors. An ion sensitive field effect transistor (ISFET), a micro hydrogen peroxide electrode and a micro oxygen electrode were used as transducers for these microbiosensors. This paper deals recent progress in the development of biosensors and microbiosensors