TY - JOUR
T1 - A self-locking technique with fast response and high sensitivity for micro-cantilever based sensing of analytes
AU - Mehta, A.
AU - Muralidharan, G.
AU - Passian, A.
AU - Cherian, S.
AU - Ferrell, T. L.
AU - Thundat, T.
PY - 2002
Y1 - 2002
N2 - MEMS based microcantilevers have been employed as sensors in both liquid and ambient conditions. One scheme for detection is based upon monitoring the change in microcantilever resonant frequency as a function of the adsorbed analyte concentration. However, the sensitivity is limited by the accuracy of the frequency measurements, which is a function of the Q-factor of the vibrating element and the measurement bandwidth. In this paper, we present a feedback scheme for self-locking amplification of the small-amplitude thermal oscillations of the microcantilever. Using this approach, we demonstrate an improvement in the Q-factor by two to three orders of magnitude as compared to that of the undriven microcantilever. Use of this technique eliminates the need for lock-in detection and results in improved response times for sensor applications. Experiments using the proposed feedback amplification technique show improved sensitivity for the detection of biological molecules in liquids, and for adsorbed vapors under ambient conditions.
AB - MEMS based microcantilevers have been employed as sensors in both liquid and ambient conditions. One scheme for detection is based upon monitoring the change in microcantilever resonant frequency as a function of the adsorbed analyte concentration. However, the sensitivity is limited by the accuracy of the frequency measurements, which is a function of the Q-factor of the vibrating element and the measurement bandwidth. In this paper, we present a feedback scheme for self-locking amplification of the small-amplitude thermal oscillations of the microcantilever. Using this approach, we demonstrate an improvement in the Q-factor by two to three orders of magnitude as compared to that of the undriven microcantilever. Use of this technique eliminates the need for lock-in detection and results in improved response times for sensor applications. Experiments using the proposed feedback amplification technique show improved sensitivity for the detection of biological molecules in liquids, and for adsorbed vapors under ambient conditions.
UR - http://www.scopus.com/inward/record.url?scp=0036959051&partnerID=8YFLogxK
U2 - 10.1557/proc-723-o6.7
DO - 10.1557/proc-723-o6.7
M3 - Conference article
AN - SCOPUS:0036959051
SN - 0272-9172
VL - 723
SP - 167
EP - 172
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
T2 - Moleculary Imprinted Materials - Sensors and Other Devices
Y2 - 2 April 2002 through 5 April 2002
ER -