Electrochemically mediated multi-modal detection strategy-driven sensor platform to detect and quantify pesticides

With the emergence of modern agronomy practices and the use of multiple synthetic pesticide agents to keep control over crop and field throughput, there lies a broad requirement for smart, accessible technologies to track pesticide contaminants in food, water, and other environmental matrices. In this work, we report at a proof of feasibility level, a sensor system to perform pesticide detection in aqueous buffers for two pesticides at the opposite ends of polarity (Atrazine and Glyphosate) in a serially combinatorial manner. The sensor construct employs a universal FR-4 substrate gold interdigitated electrodes with active sensing elements based on selective antibodies (proteins) and polymeric network structures - poly(3,4-ethylenedioxythiophene). Further, to determine metrics of sensor deployment in real-case scenarios: multi-modal (electrochemical impedance spectroscopy and chronoamperometry) and multi-approach strategies (affinity-binding and receptor-free) were used to obtain sensing measurements. Higher specificity repeatable outputs were obtained with the affinity-based method while greater sensitivity by means of dynamic range (0.5 ng/ml-10 mu g/ml for Glyphosate and 10 fg/ml-1 ng/ml for Atrazine) and limit of detection (0.5 ng/ml for Glyphosate and 1 fg/ml for Atrazine) was determined via receptor-free direct approach for both pesticides. This serves as a first-step study to perform potential combinatorial assessment and subsequently-multiplexed analysis of pesticide antigens.