Metal Enhanced Electrochemical Cyclooxygenase-2 (COX-2) Sensor for Biological Applications

Pain measurement is commonly required in biomedical and other emergency situations, yet there has been no pain biosensor reported in literature. Conventional approaches for pain measurement relies on Wong-Baker face diagrams, which are grossly inadequate for situations involving children or unconscious people. We report a label-free immunosensor for monitoring the pain biomarker cylooxygenase-2 (COX-2) in blood. The sensor is based on the concept of metal-enhanced detection (MED). MED relies on the idea that the immobilization of underpotential deposition (upd) metallic films deposited either as a monolayer or electrostatically held onto a solid gold substrate could significantly amplify bimolecular recognition such as involving antigen-antibody (Ab-Ag) interactions. The surface bound Ab-Ag complex insulates the electrode; causing a decrease in concentration-dependent redox signals. A linear detection range of (3.64-3640.00)×10^-4ng/mL was recorded with a detection limit of 0.25×10^-4ng/mL, which was 4 orders of magnitude lower than that reported for ELISA for the same biomarker. The immunosensor exhibited selectivity of less than 6% for potential interferents.