Paper biosensors utilize silver nanoparticles for onsite pesticide residue detection

Abstract

The improper use of pesticides and excessive doses in the long term contribute to climate change and even threaten human health, organisms, and the balance of the ecosystem. A pesticide detection device is needed to monitor its levels to minimize risks to human health and the environment. A paper biosensor was developed in this study to detect organophosphates by utilizing the enzyme acetylcholine esterase (AChE) and silver nanoparticles (AgNP). The Whatman filter paper was used as a visual OP detection zone. AgNP, as an indicator, is adsorbed and gives a brownish-yellow color to the paper, while AChE is immobilized into the film and layered on the paper. The addition of acetylthiocholine chloride as a substrate to the film released thiocholine products which could replace the capping AgNPs causing the AgNPs to aggregate and the paper color to pale. The presence of OP in the sample will inhibit AChE activity so that paper fading is reduced. The biosensor response is quantized as an RGB value, which is determined using an application on a smartphone. The resulting biosensor has excellent performance with a linear range of 0.05-2.00 mg/L, a detection limit of 0.04 mg/L, and a CV of 0.48%. Biosensor measurements on vegetable samples showed conformity with the GCMS results as the standard method. Therefore, this biosensor is suitable for the on-site detection of pesticides offering easy, fast, and inexpensive analysis.