Loading…

Stochastic Sensing of Single Molecules in a Nanofluidic Electrochemical Device

We report the electrochemical detection of individual redox-active molecules as they freely diffuse in solution. Our approach is based on microfabricated nanofluidic devices, wherein repeated reduction and oxidation at two closely spaced electrodes yields a giant sensitivity gain. Single molecules e...

Full description

Saved in:
Bibliographic Details
Published in:Nano letters 2011-07, Vol.11 (7), p.2881-2886
Main Authors: Zevenbergen, Marcel A. G, Singh, Pradyumna S, Goluch, Edgar D, Wolfrum, Bernhard L, Lemay, Serge G
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report the electrochemical detection of individual redox-active molecules as they freely diffuse in solution. Our approach is based on microfabricated nanofluidic devices, wherein repeated reduction and oxidation at two closely spaced electrodes yields a giant sensitivity gain. Single molecules entering and leaving the cavity are revealed as anticorrelated steps in the faradaic current measured simultaneously through the two electrodes. Cross-correlation analysis provides unequivocal evidence of single molecule sensitivity. We further find agreement with numerical simulations of the stochastic signals and analytical results for the distribution of residence times. This new detection capability can serve as a powerful alternative when fluorescent labeling is invasive or impossible. It further enables new fundamental (bio)electrochemical experiments, for example, localized detection of neurotransmitter release, studies of enzymes with redox-active products, and single-cell electrochemical assays. Finally, our lithography-based approach renders the devices suitable for integration in highly parallelized, all-electrical analysis systems.
ISSN:1530-6984
1530-6992
DOI:10.1021/nl2013423