Microfluidic aptameric affinity sensing of vasopressin for clinical diagnosis and therapeutic applications

ThaiHuu Nguyen, Renjun Pei, Donald W. Landry, Milan N. Stojanovic and Qiao Lin Department of Mechanical Engineering, Columbia University, New York, NY 10027; Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, Columbia University, New York, NY 10032 Abstract: We present a microfluidic aptameric biosensor, or aptasensor, for selective detection of clinically relevant analytes with integrated analyte enrichment, isocratic elution and label-free detection by mass spectrometry. Using a microfluidic platform that is coupled to matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS), we demonstrate specific purification, enrichment, and label-free detection of trace amounts of arginine vasopressin (AVP), a peptide hormone that is responsible for arterial vasoconstriction. During extreme physical trauma, in particular immunological shock or congestive heart failure, AVP is excreted abnormally and is hence a biomarker for such conditions. The device uses an aptamer, i.e., an oligonucleotide that binds specifically to an analyte via affinity interactions, to achieve highly selective analyte capture and enrichment. In addition, via thermally induced reversible disruption of the aptameranalyte binding, the device can be easily regenerated for reuse and allows isocratic analyte elution, i.e., release and collection of analytes using a single aqueous solution.