Insect Odorant Binding Protein 2 Integrated with Flow Digital Nanoplasmon-metry for Neonicotinoid Pesticide Residues Sensing in Beverages

Abstract

Neonicotinoid is one class of the most used pesticides to repel pests. They demonstrated good efficiency but meanwhile pollute the ecosystem. Therefore, its abuse is an ever-thorny problem. Furthermore, since the multi-pesticide association is commonly used for high-efficient crop protection from pests in farms, quickly screening the pesticide contamination sorted by class is much more efficient and more accessible for on-site use. In this work, a novel and promising strategy that incorporated the neonicotinoid-specific odorant binding protein 2 (OBP2) with ultra-sensitive local surface plasmon resonance (LSPR)-based measurement, the flow digital nanoplasmon-metry (flow DiNM) was proposed. OBP2 modified on gold nanoparticles acted as the seizer to simultaneously capture neonicotinoids, such as imidacloprid, dinotefuran, and acetamiprid. The flow DiNM comprises spectral image contrast and digital analysis to enhance the slight LSPR change by the small molecule, neonicotinoid pesticides, attaching. It shows prominent LODs of 3.6, 7, and 15.3 ppb in imidacloprid, acetamiprid, and dinotefuran within the 45-minute detection. Furthermore, the blind tests show a high consistency to the standard method, and the recovery of true positives was 83% and 87.5% for green and black teas, respectively, and the recovery of true negatives can achieve 100 % with a total of 18 tests. Compared to conventional antibody-based immunoassay, the production of OBPS that uses E. coil protein expression takes advantage of high yield, time-saving, and cost-effectiveness. Together with its broad while specific neonicotinoid pesticides binding affinity and sensitivity of flow DiNM, this work demonstrated much higher accessibility to the on-site end users.