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 (nanoCaCO(3)-chi) composite film fabricated by a one-step co-electrodeposition method. The generated nanoCaCO(3)-based matrix possessed a three-dimensional (M) 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 mu g 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. (C) 2009 Elsevier B.V. All rights reserved.