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Originally published in Science Express on 2 February 2006
Science 17 March 2006:
Vol. 311. no. 5767, pp. 1592 - 1595
DOI: 10.1126/science.1122588
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Reports

MOSFET-Embedded Microcantilevers for Measuring Deflection in Biomolecular Sensors

Gajendra Shekhawat,1,2* Soo-Hyun Tark,3 Vinayak P. Dravid1,2,3*

A promising approach for detecting biomolecules follows their binding to immobilized probe molecules on microfabricated cantilevers; binding causes surface stresses that bend the cantilever. We measured this deflection, which is on the order of tens of nanometers, by embedding a metal-oxide semiconductor field-effect transistor (MOSFET) into the base of the cantilever and recording decreases in drain current with deflections as small as 5 nanometers. The gate region of the MOSFET responds to surface stresses and thus is embedded in silicon nitride so as to avoid direct contact with the sample solution. This approach, which offers low noise, high sensitivity, and direct readout, was used to detect specific binding events with biotin and antibodies.

1 International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208, USA.
2 NUANCE Center, Northwestern University, Evanston, IL 60208, USA.
3 Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.

* To whom correspondence should be addressed. E-mail: g-shekhawat{at}northwestern.edu; v-dravid{at}northwestern.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Free-Solution, Label-Free Molecular Interactions Studied by Back-Scattering Interferometry.
D. J. Bornhop, J. C. Latham, A. Kussrow, D. A. Markov, R. D. Jones, and H. S. Sorensen (2007)
Science 317, 1732-1736
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