Research Highlights

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  • Biotechnology

Published online: 8 August 2007 | doi:10.1038/nchina.2007.154

Sensors: A snappy detector

Anne Pichon

Introduction

© (2007) RSC

Aptamers are single-stranded DNA or RNA 'probes' that can recognize and bind to specific targets within a large library of randomly created molecules. They have been widely used as 'aptasensors' for detecting different molecules including proteins and organic dyes. However, current aptasensors require a complicated process of labelling probes onto the DNA or targets, and the expensive probes can often be used only once. Shaojun Dong and co-workers at the Chinese Academy of Sciences in Changchun and Beijing have now made a label-free reusable aptasensor¹ based on electrochemical impedance spectroscopy (EIS) — a technique for detecting impedance variations of aptasensing systems, such as probe molecules on a sensing surface.

In their study, the researchers used adenosine as the target molecule. They fabricated a sensing interface by treating a gold surface, which is attached to an EIS system, with a DNA duplex that comprises an adenosine-binding aptamer (ABA) strand and a part complementary strand (PCS). If adenosine is present in the system, the duplex will lose its relatively longer ABA to the target molecule, but keep the shorter PCS on the gold surface (see image). The shorter probe will then reduce the impedance of the system, which in turn can be detected by the EIS.

This approach not only skips the probe-labelling process, but also provides a regeneration ability of the sensing interface by treating it with ABA. Moreover, it does not depend on the molecule size or the structural change of the aptamer, and therefore has applications for a wider range of targets.

The authors of this work are from:
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China; Graduate University of the Chinese Academy of Sciences, Beijing, China.

References

1. Li, B., Du, Y., Wei, H. & Dong, S. Reusable, label-free electrochemical aptasensor for sensitive detection of small molecules. Chem. Commun. doi: 10.1039/b707057h (2007).  | Article |