One-step fabrication of three-dimensional porous calcium carbonate–chitosan composite film as the immobilization matrix of acetylcholinesterase and its biosensing on pesticide

This work reports on a novel nanosized calcium carbonate–chitosan (nanoCaCO3–chi) composite film fabricated by a one-step co-electrodeposition method. The generated nanoCaCO3-based matrix possessed a three-dimensional (3D) porous, network-like structure, providing a favorable and biocompatible microenvironment to immobilize enzyme. By using such a composite film as enzyme immobilization matrix, a highly sensitive and stable acetylcholinesterase (AChE) sensor was achieved for determination of methyl parathion as a model of organophosphate pesticides (OPs) compounds. The inhibition of methyl parathion was proportional to its concentration ranging from 0.005–0.2 to 0.75–3.75 μg mL−1. The detection limit was found to be as low as 1 ng mL−1 (S/N = 3). The designed biosensor exhibited good reproducibility and acceptable stability.