A Nanobiosensor Based on 4-Hydroxyphenylpyruvate Dioxygenase Enzyme for Mesotrione Detection

Abstract

The herbicide residue from intensive agricultural activity provokes environmental disturbances and human health injuries. Among the enzymatic disruptor herbicides, mesotrione is able to inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD), which plays a key role in the carotenoid synthesis. Therefore, enzyme-based sensors are innovative options for monitoring herbicides used in agriculture. Compared to the standard sensors, biosensors have assorted advantages, such as practicality, quick response, low cost, and high sensitivity. A nanobiosensor was developed herein based on HPPD for mesotrione detection. Theoretically, the molecular docking and molecular dynamics simulation estimated the interacting regions of HPPD with mesotrione. Experimentally, the atomic force microscope tip functionalization with HPPD immobilized in self-assembled monolayers was confirmed by fluorescence microscopy and atomic force spectroscopy. The cross-linker N-(3-dimethylaminopropyl)- $\mathrm{N}^\prime $ -ethylcarbodiimide hydrochloride was responsible for properly preserving the enzyme on the tip. The nanobiosensor proposed here was successfully able to detect mesotrione molecules. Such effectiveness in the development of nanobiosensors promises reliable, precise, and low-cost techniques, which apply to a broad range of issues, from ecology to medicine.