The visual detection of anesthetics in fish based on an inverse opal photonic crystal sensor

A novel smart sensor for the rapid and label-free detection of benzocaine has been developed based on the combination of photonic crystal (PC) and molecular imprinting polymer (MIP) techniques. A molecularly imprinted photonic crystal (MIPC) hydrogel film was prepared via a non-covalent, self-assembly approach with a PC mould. With a highly ordered inverse opal structure, the resulting benzocaine MIPC exhibited high sensitivity, smart specificity, quick response times and good regeneration abilities. It can give rise to a readable optical signal and color change upon binding with benzocaine, with a detection limit of 16.5 μg mL^-1. The sensor has been successfully used to visually estimate benzocaine concentrations in fish samples. In comparison with HPLC, the developed MIPC sensor has shown satisfactory accuracy in terms of results. It has great potential for on-site screening and the visual detection of trace benzocaine in real samples.