Detection of sterigmatocystin using a smartphone-assisted colorimetric sensing method based on a self-designed portable device with hydrogel.

Abstract

Sterigmatocystin (ST) is a precursor substance of aflatoxin B1 (AFB1). In this study, a colorimetric sensor based on ionic liquid-enhanced hydrogel encapsulating Au@Cu2O nanozymes was developed. Combined with a self-designed portable device, the constructed colorimetric sensor was used for on-site rapid detection of ST. In the presence of ST, it specifically binded to the ST aptamer, leading to the collapse of hydrogel and the release of Au@Cu2O nanoparticles synthesized via the seed-growth method, which could catalyze the colorimetric system. With a self-programmed "Toxin Recognition" app, the portable colorimetric device was developed for the detection of ST ranging from 0.5 ng g-1 to 260 ng g-1 with the detection limit of 0.33 ng g-1. It was applied for the detection of ST in nine agricultural samples, and matrix effects were 72.48%-94.27%. This work has broadened the scope of hydrogel-based colorimetric sensing and imposed great improvement in the early warning of AFB1.

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