Novel electrochemical biosensor based on core-shell nanostructured composite of hollow carbon spheres and polyaniline for sensitively detecting malathion

A novel electrochemical biosensor was constructed by anchoring acetylcholine esterase (AChE) onto the core-shell nanostructured composite of hollow carbon spheres coated with needle-like polyaniline (denoted by HCS@PANI), and used for rapid determination of malathion, which was established based on the chemisorption/desorption process of AChE used as an indicator. The uniformly distributed HCS was wrapped with the needle-like PANI nanowires to form the HCS@PANI nanocomposite, which not only exhibits high specific surface area and chemical functionality but also possesses strong electrochemical activity. After AChE was adsorbed onto the HCS@PANI nanocomposite, the electrochemical catalysis of AChE/HCS@PANI-based biosensor towards acetylthiocholine chloride (ATCl) was inhibited in the presence of malathion, which was applied to detect malathion, and the biosensor exhibited a low detection limit of 0.16   ng   mL −1 within a linear range from 1.0   ng   mL −1 to 10   μg   mL −1 of the malathion concentration. Also, the results suggested that the developed electrochemical biosensor showed high selectivity, good reproducibility, and applicability for malathion detection, indicating that the proposed method using the HCS@PANI nanocomposite as the sensitive layer for the AChE immobilization and catalysis of ATCl has potential application in high-sensitive pesticide determinations.