Label-free electrochemical monitoring of vasopressin in aptamer-based microfluidic biosensors.

Vasopressin is an indicating biomarker for blood pressure in the human body and low vasopressin levels can be indicative of late-phase hemorrhagic shock or other traumatic injuries. In this paper we have developed an aptamer-based label-free microfluidic biosensor for the electrochemical detection of vasopressin. The detection area consists of aptamers immobilized on carbon nanotubes which specifically capture the vasopressin molecules in solution resulting in changes in conductivity across the sensor. We report a limit of detection of 43 pM in standard solutions and demonstrate high detection specificity toward vasopressin when different interferents are present. The miniaturized microfluidic biosensor offers continuous monitoring of different vasopressin levels with good potential for portability. Ultimately such a system could serve as a point-of-care diagnostics tool for patients with excessive bleeding when standard medical infrastructure is not available.