title: Continuous, real-time monitoring of cocaine in undiluted blood serum via a microfluidic, electrochemical aptamer-based sensor.
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. 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 (approximately 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.
authors.affiliation: Department of Materials, University of California, Santa Barbara, California 93106, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Swensen
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ferguson
authors.forename: Arica A
authors.initials: AA
authors.lastname: Lubin
authors.forename: Rebecca Y
authors.initials: RY
authors.lastname: Lai
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Heeger
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Plaxco
authors.forename: H Tom
authors.initials: HT
authors.lastname: Soh
mesh_terms: D052157:Aptamers, Nucleotide; D015374:Biosensing Techniques / Q000295:instrumentation; D003042:Cocaine / Q000032:analysis* / Q000097:blood*; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D046210:Microfluidic Analytical Techniques; D044085:Microfluidics / Q000295:instrumentation; D055095:Optics and Photonics; D044967:Serum; D013997:Time Factors
chemical_list: D052157:Aptamers, Nucleotide; D004247:DNA; D003042:Cocaine