THE CONSTRUCTION OF MICROCALORIMETRIC BIOSENSORS BY USE OF HIGH-RESOLUTION THIN-FILM THERMISTORS

A new calorimetric biosensor has been developed using thin-film thermistor arrays and immobilized enzymes. The miniaturized thermistors produced on glass substrates, exhibit a high sensitivity of 2%/K (TCR), a temperature resolution of 0.1 mK, a rise-time of 3 ms and high reproducibility of resistance and TCR. The life time in physiological solution is at least three months. Additionally this device can be miniaturized and integrated on different substrate materials. A Peltier thermostat with a temperature stability of 1 mK was built up containing two thermistor arrays which were inserted into a flow-through system to enable the detection of the heat produced by an enzyme reaction in a differential mode. Covalently immobilized glucose oxidase and catalase on controlled pore glass (CPG) were used to demonstrate the high sensitivity of the produced thermistor arrays.