Tao_2022_Anal.Methods__

Electrode materials play a central role in assembling biosensors. In this work, a titanium dioxide nanoparticle loaded graphitized carbon nanofiber (TiO(2)/GNF) composite is prepared for the sensitive detection of organophosphorus pesticide residues (OPs). The TiO(2)/GNF composite with superior conductivity, catalytic activity and biocompatibility offers an extremely hydrophilic surface for the effective immobilization of acetylcholinesterase (AChE). Furthermore, the Ti atoms of TiO(2)/GNFs could coordinate with AChE to improve its stability, and TiO(2) has a strong adsorption on OPs. The developed AChE/TiO(2)/GNFs/GCE biosensor showed a high affinity to acetylthiocholine chloride (ATCh) and could catalyze the hydrolysis of ATCh with an apparent Michaelis-Menten constant (K(m)) of 50 microM. The constructed AChE/TiO(2)/GNFs/GCE biosensor exhibits a wide detection linear range (1.0 x 10(-13) M to 1.0 x 10(-8) M) with a low detection limit (3.3 fM) for paraoxon determination (a model of OPs). In addition, the developed biosensor possesses remarkable anti-interference, acceptable reproducibility and good long-term stability, and is successfully used for the determination of OPs in lake water, providing a new strategy for the analysis of OPs in ecological environments.