NEW MICROPOTENTIOSTAT FOR MEASUREMENT RESPONSES FROM THICK-FILM SENSORS

The new solution of an amperometric sensor currents measurement is given. It solves the problem of measurement of low currents (in order of nanoamps) provided by electrochemical biosensors. However the sensitivity of integrated measurement system, which is processing output currents provided by biosensor, has to be in order of picoamps. There are leakage currents and noise constraints which could be avoided by on-chip solution. The on-chip solution allows direct chip connection with a biosensor structure directly on its basic ceramic plate. It means the idea is similar to hybrid integrated circuit. Main advantage of this solution is separating sensitive low potential and low current ASIC electronics placed just on the TFT sensor from control and supply electronics of evaluating portable instrument. Additional advantages of the sensors fabricated using TFT are low cost, small dimensions, good reproducibility, chemical, mechanical and electrical properties of electrodes and well accessible and ecological fabrication process.