Continuous, real-time monitoring of cocaine in undiluted blood serum via a microfluidic, electrochemical aptamer-based sensor

James S. Swensen, Yi Xiao, Brian S. Ferguson, Arica A. Lubin, Rebecca Y. Lai, Alan J. Heeger, Kevin W. Plaxco, H. Tom Soh

Research output: Contribution to journalArticle

225 Scopus citations


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. Toward 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 min 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 groundwork for the real-time, point-of-care detection of a wide variety of molecular targets.

Original languageEnglish (US)
Pages (from-to)4262-4266
Number of pages5
JournalJournal of the American Chemical Society
Issue number12
StatePublished - Apr 1 2009


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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