(12b) Nanoparticle-Based Phosphorylated Butyrylcholinesterase Electrochemical Immunosensor for Biomonitoring of Organophosphorus Nerve Agents Exposure

We present a truly cost-effective disposable electrochemical immunosensor for simple, fast and sensitive detection of alkylphosphorylated butyrylcholinesterase (BChE), a biomarker of organophosphate (OP) nerve agent exposure. Our new approach takes the advantage of a disposable screen-printed electrode (SPE) coated with zirconia nanoparticle to immobilize OP-BChE adducts and follows by quantum dot-tagged anti-BChE antibodies as quantifying affinity agents. The captured CdSe-quantum dot (QD) tags are measured by electrochemical stripping analysis of the metallic component (cadmium) after dissolving the QD in acid. Nerve agents, Sarin and Soman were used to prepare OP-modified BChE (OP-BChE) in this study. The electrochemical immunosensor has demonstrated a highly linear voltammetric response over the 0.05 to 3 nM range of OP-BChE. with high sensitivity of 0.026 nM (based on S/N=3), high stability & selectivity, and good precision (RSD = 4.5%). Also, the immunosensor has been successfully detected OP-BChE adducts in the plasma of the mice which have been dosed with 1mg/kg of the nerve agent model compound of Soman. This novel nanoparticle-based electrochemical immunosensor thus opens up new pathways for designing simple, fast, sensitive, and cost-effective sensing platform for on-site testing of a variety of organophosphate (OP) nerve agent exposure.