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Published Online February 2, 2006
Science DOI: 10.1126/science.1122588

Reports

Submitted on November 14, 2005
Accepted on January 20, 2006

MOSFET-Embedded Microcantilevers for Measuring Deflection in Biomolecular Sensors

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

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

* To whom correspondence should be addressed.
Gajendra Shekhawat , E-mail: g-shekhawat{at}northwestern.edu
Vinayak P. Dravid , E-mail: v-dravid{at}northwestern.edu

A promising approach for detecting biomolecules follows their binding to immobilized target molecules on microfabricated cantilevers; binding causes surface stresses that bend the cantilever. We measure 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.


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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Science. ISSN 0036-8075 (print), 1095-9203 (online)