Porous Fe/CeO2 Nanozyme-Based Hydrogel Colorimetric Platform for on-Site Detection of Kanamycin

Theportable and sensitive hydrogel-based colorimetric sensorcould realize on-site detection of antibiotic residues in environmentand food. Excessiveuse of antibiotics causes their residues in the environmentand food, seriously threatening ecosystem and human health. Designinga portable and sensitive sensor for on-site analysis of antibioticsis therefore in high demand. In this study, we have developed a smartphone-capablehydrogel colorimetric platform for ultrasensitive detection of kanamycin(KAN) based on aptamer-regulated nanozyme activity. The synthesizedFe/CeO2 hexagonal bipyramidal microcrystals (Fe/CeO2 HBs) exhibited excellent peroxidase-like activity, but itcould be obviously inhibited by the aptamer, and the inhibition effectwas further enhanced with the specific recognition between targetand aptamer, making it possible to design a facile colorimetric methodfor KAN analysis. Moreover, the aptamer-functionalized Fe/CeO2 HBs (Fe/CeO2 HBs@Apt) were introduced into thehydrogel to fabricate a portable analytical tube, whose colorimetricsignal was read out by a smartphone platform, realizing the on-siteanalysis of KAN. The linear response range was 0.05-48.45 ngmL(-1) with an ultralow detection limit of 0.035 ngmL(-1) and the recovery rate ranging from 99.57 to103.76% for spiked real samples, demonstrating its superior accuracyand reliability. This work provides new insights into designing thesolid-phase hydrogel-based colorimetric method for on-site analysisof antibiotic residues.

Automated summary

A portable and sensitive hydrogel-based colorimetric sensor was developed for on-site detection of antibiotic residues. It plays a crucial role in protecting the ecosystem and human health by designing a portable and sensitive sensor for on-site analysis.