An ultra-sensitive ΔR/R measurement system for biochemical sensors using piezoresistive micro-cantilevers

Nag, Sudip ; Kale, N. S. ; Rao, V. R. ; Sharma, D. K. (2009) An ultra-sensitive ΔR/R measurement system for biochemical sensors using piezoresistive micro-cantilevers 31st Annual International Conference of theIEEE Engineering in Medicine and Biology Society (EMBC'09) . pp. 3794-3797. ISSN 1557-170X

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Official URL: http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumb...

Related URL: http://dx.doi.org/10.1109/IEMBS.2009.5334434

Abstract

Piezoresistive micro-cantilevers are interesting bio-sensing tool whose base resistance value (R) changes by a few parts per million (DeltaR) in deflected conditions. Measuring such a small deviation is always being a challenge due to noise. An advanced and reliable ΔR/R measurement scheme is presented in this paper which can sense resistance changes down to 6 parts per million. The measurement scheme includes the half-bridge connected micro-cantilevers with mismatch compensation, precision op-amp based filters and amplifiers, and a lock-in amplifier based detector. The input actuating sine wave is applied from a function generator and the output dc voltage is displayed on a digital multimeter. The calibration is performed and instrument sensitivity is calculated. An experimental set-up using a probe station is discussed that demonstrates a combined performance of the measurement system and SU8-polysilicon cantilevers. The deflection sensitivity of such polymeric cantilevers is calculated. The system will be highly useful to detect bio-markers such as myoglobin and troponin that are released in blood during or after heart attacks.

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Deposited On:28 Jan 2012 11:57
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