Noble-metal-free high-entropy alloy aerogels with peroxidase-like activity mediated bioenzyme-free colorimetric sensor for portable and rapid detection of glyphosate

Noble-metal-free high-entropy alloy nanozyme was synthesized in a facile way. • A bioenzyme-free sensor was constructed for direct and rapid sensing of Gly. • This sensor shows high sensitivity and selectivity for Gly detection. • Smartphone-assisted hydrogel kit can realize point-of-care testing of Gly. It is urgently needed to exploit an effective technique for point-of-care testing (POCT) of glyphosate (Gly). Herein, we synthesized a high entropy alloy aerogel (FeCoNiCuMn HEAAs) nanozyme for quick and portable detection of Gly. The FeCoNiCuMn HEAAs with excellent peroxidase (POD)-mimetic activity can catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation to blue oxTMB in the presence of H 2 O 2 . Gly can restrain the POD-mimetic activity of FeCoNiCuMn HEAAs due to the coordination between the FeCoNiCuMn HEAAs and Gly via P–O–Cu and P–O–Fe, leading to a decreased absorbance of the system. Leveraging this mechanism, a bioenzyme-free mediated colorimetric sensor was designed for Gly detection. This colorimetric sensor displays high specificity and sensitivity for Gly. Given its simplicity and bioenzyme-free participation, a smartphone-assisted hydrogel kit was also constructed for the POCT of Gly. The potential application of the colorimetric sensor and hydrogel kit was verified by detecting the Gly in foods. Download: Download high-res image (157KB) Download: Download full-size image