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Proceedings Paper

Electrochemical quantum tunneling for electronic detection and characterization of biological toxins
Author(s): Chaitanya Gupta; Ross M. Walker; Rishi Gharpuray; Max M. Shulaker; Zhiyong Zhang; Mehdi Javanmard; Ronald W. Davis; Boris Murmann; Roger T. Howe
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Paper Abstract

This paper introduces a label-free, electronic biomolecular sensing platform for the detection and characterization of trace amounts of biological toxins within a complex background matrix. The mechanism for signal transduction is the electrostatic coupling of molecule bond vibrations to charge transport across an insulated electrode-electrolyte interface. The current resulting from the interface charge flow has long been regarded as an experimental artifact of little interest in the development of traditional charge based biosensors like the ISFET, and has been referred to in the literature as a "leakage current". However, we demonstrate by experimental measurements and theoretical modeling that this current has a component that arises from the rate-limiting transition of a quantum mechanical electronic relaxation event, wherein the electronic tunneling process between a hydrated proton in the electrolyte and the metallic electrode is closely coupled to the bond vibrations of molecular species in the electrolyte. Different strategies to minimize the effect of quantum decoherence in the quantized exchange of energy between the molecular vibrations and electron energy will be discussed, as well as the experimental implications of such strategies. Since the mechanism for the transduction of chemical information is purely electronic and does not require labels or tags or optical transduction, the proposed platform is scalable. Furthermore, it can achieve the chemical specificity typically associated with traditional micro-array or mass spectrometry-based platforms that are used currently to analyze complex biological fluids for trace levels of toxins or pathogen markers.

Paper Details

Date Published: 7 May 2012
PDF: 14 pages
Proc. SPIE 8373, Micro- and Nanotechnology Sensors, Systems, and Applications IV, 837303 (7 May 2012); doi: 10.1117/12.920692
Show Author Affiliations
Chaitanya Gupta, Stanford Univ. (United States)
Ross M. Walker, Stanford Univ. (United States)
Rishi Gharpuray, Stanford Univ. (United States)
Max M. Shulaker, Stanford Univ. (United States)
Zhiyong Zhang, Stanford Univ. (United States)
Mehdi Javanmard, Stanford Univ. School of Medicine (United States)
Ronald W. Davis, Stanford Univ. School of Medicine (United States)
Stanford Univ. School of Medicine (United States)
Boris Murmann, Stanford Univ. (United States)
Roger T. Howe, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 8373:
Micro- and Nanotechnology Sensors, Systems, and Applications IV
Thomas George; M. Saif Islam; Achyut Dutta, Editor(s)

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