Immobilization of acetylcholinesterase on SnSe₂ hollow spheres for sensitive detection of phoxim

A simple method for immobilization of acetylcholinesterase (AChE) on SnSe₂ hollow spheres for detection of phoxim was described. SnSe₂ hollow spheres were prepared by hydrothermal methods and were characterized by TEM. The immobilized AChE retained its biological activity well and could catalyze the hydrolysis of acetylthiocholine to form thiocholine, which was then oxidized to produce detectable signal. Based on the inhibition toward the enzymatic activity of AChE by phoxim, under optimal conditions, the sensors could be used for the determination of phoxim ranging from 0.008 to 56 μg/mL with the detection limit of 0.004 μg/mL. The developed phoxim biosensors exhibited good stability and reproducibility. This work demonstrated that SnSe₂ hollow sphere could be served as an ideal carrier for immobilization of AChE to fabricate corresponding biosensor.