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Title An ultra-sensitive delta R/R measurement system for biochemical sensors using Piezoresistive Micro-Cantilevers
 
Names NAG, S
KALE, NS
RAO, VR
SHARMA, DK
Date Issued 2009 (iso8601)
Abstract Piezoresistive micro-cantilevers are interesting bio-sensing tool whose base resistance value (R) changes by a few parts per million (Delta R) in deflected conditions. Measuring such a small deviation is always being a challenge due to noise. An advanced and reliable Delta R/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.
Genre Proceedings Paper
Identifier EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20,3794-3797