Potentiometric Biosensors Based on Silicon and Porous Silicon
I. Basu, R.V. Subramanian, A. Mathew, A. Chadha and E. Bhattacharya
Indian Institute of Technology Madras, IN
Keywords: biosensor, EISCAP, triglyceride, urea, porous silicon
Detection and estimation of Triglycerides and Urea are clinically important. We report fabrication of potentiometric biosensors based on silicon and porous silicon and estimation of triglycerides and urea based on enzymatic reactions. The sensor is an ElectrolyteInsulator-Semiconductor capacitor (EISCAP) that shows a shift in the measured CV with changes in the pH of the electrolyte. Many biological reactions, especially enzyme mediated ones, involve changes in the pH of the electrolyte and an EISCAP can be effectively used as a biosensor. We have earlier reported on an EISCAP sensor, where the semiconductor was porous silicon and the insulator was SiO2, for Tributyrin - a short chain triglyceride which produced butyric acid on hydrolysis in the presence of the enzyme lipase. Use of silicon nitride as the insulator has advantages over SiO2 since the nitride is stable in contrast to SiO2, which dissolves in basic solutions allowing for the possibility of detection extended to the basic range. The sensor with nitride as the insulator is calibrated for estimation of Tributyrin and Urea. Results are reported on both silicon and porous silicon as the semiconductor layer.
Nanotech 2004 Conference Technical Program Abstract