Continuous, Real-Time Monitoring of Cocaine in Undiluted Blood Serum via a Microfluidic, Electrochemical Aptamer-Based Sensor

Authors

James S. Swensen, University of California, Santa Barbara
Yi Xiao, University of California, Santa Barbara
Brian S. Ferguson, University of California, Santa Barbara
Arica A. Lubin, University of California, Santa Barbara
Rebecca Lai, University of Nebraska - LincolnFollow
Alan J. Heeger, University of California, Santa Barbara
Kevin W. Plaxco, University of California, Santa Barbara
H. Tom. Soh, University of California, Santa Barbara

Date of this Version

2009

Citation

J Am Chem Soc. 2009 April 1; 131(12): 4262–4266.

Comments

Copyright © 2009 American Chemical Society

Abstract

The development of a biosensor system capable of continuous, real-time measurement of small-molecule analytes directly in complex, unprocessed aqueous samples has been a significant challenge, and successful implementation has been achieved for only a limited number of targets. Towards a general solution to this problem, we report here the Microfluidic Electrochemical Aptamer-based Sensor (MECAS) chip wherein we integrate target-specific DNA aptamers that fold, and thus generate an electrochemical signal, in response to the analyte with a microfluidic detection system. As a model, we demonstrate the continuous, real-time (~1 minute time resolution) detection of the small molecule drug cocaine at near physiological, low micromolar concentrations directly in undiluted, otherwise unmodified blood serum. We believe our approach of integrating folding-based electrochemical sensors with miniaturized detection systems may lay the ground work for the realtime, point-of-care detection of a wide variety of molecular targets.