Development of a biosensor for rapid detection of insecticide based on insect-derived chemosensory proteins and graphene nanocellulose paper

Abstract. This research aims to develop a low-cost, disposable tool for rapid point of use detection of pesticides. The electrochemical biosensor is based on insect-derived chemosensory proteins (CSP) assembled to platinum-functionalized graphene paper electrodes. CSPs were extracted from Solenopsis invicta (Si, red imported fire ant) and Glossina morsitans morsitans (Gmm, tsetse fly) and then expressed and His-tagged. Paper electrodes were fabricated with nanocellulose crystalline films and graphene ink, and then nanoplatinum was deposited onto the working surface using pulsed sonoelectrodeposition. His-tagged CSPs were then assembled onto the electrodes via polyhistidine-platinum covalent bonding. CSP immobilization and pesticide detection were characterized by measuring the charge transfer resistance derived from electrochemical impedance spectroscopy (EIS). We show that these biosensors are valid for detecting imidacloprid (a neonicitniod insecticide), with sensitivity of 4.076±0.26 Ω/μM, 5.6 μM limit of detection and 2 minutes response time. Ongoing works are testing the sensitivity and detection limit of these electrodes for different pesticides and insecticide residuals (such as glyphosphate and glyoxylate). These preliminary results represent the first major step toward engineering CSP-based biosensors for rapidly detecting pesticides and insecticides in the field.