Talanta 43 (1996) 1163 1169 Talanta Adaptation of microthermal probes for the determination of biochemical species Volodymyr Lysenko”,b, Georges Delhomme’, Alexey Soldatkina,d, Vitaly Strikhab, Andrk Dittmar’, Nicole Jaffrezic-Renault”, Claude MarteleP* Abstract A glucose sensitive enzymatic thermal sensor based on a pair of commercial microthermal probes was fabricated by cross-linking of the corresponding enzymes (glucose oxidase and catalase) with bovine serum albumin onto the chip surfaces. The characteristics of this sensor were optimisedby testing it in different conditions. To find the maximal sensitivity, the calibration curvesof this sensor were measured in different buffer solutions with and without the addition of H,O, to the analysed samples at various ratesof sample flow stream.Different buffer solutionsand hydrogen peroxide concentraions were usedto realise the principles of a chemical and biochemical amplification of the biosensor response. It was shown that the level of the biosensor response and its dynamic range increase if hydrogen peroxide is added to the analysed samples and dependon the type of buffer solutionx testedand the rate of the sample flow stream. K~JNYW~.S: Biosensor dynamic range; Biosensor sensitivity; Chemical and biochemical amplification: Enzyme thermal sensor: Glucose -- 1. Introduction Thermal biosensorsbased on either thermocou- ples or thermopiles [l-5] have been applied suc- cessfully in biochemical analysis. The recent developments in this field were mainly focused on miniaturisation and multi-analytes capabilities offered by the micromachining and microelectron- its technologies. Another approach in the design of new low-cost biosensorsis to use a commercial probe and to modify it in order to obtain new properties. By this way it is possible to combine the well stated advantages of the original sensor __- with the new properties of the modified one to * Corresponding author. obtain a simple multisensor with the reliability of 0039.9140~961$I5.00 cc’ 1996 Elsevier Science B.V. All rights reserved PII SOO39-9140(96)01855-3