White Peroxidase-Mimicking Nanozymes: Colorimetric Pesticide Assay without Interferences of O2 and Color

Given the promising prospect of peroxidase-like nanozymes in colorimetric assay, it is interesting and significant to eliminate their oxidase-like activities and color interference for nanozyme-based colorimetric assay. Here, the enzyme-mimicking activity of GeO2 nanomaterials is discovered. GeO2 nanozymes exclusively possess peroxidase-like activity without oxidase-like characteristics, freeing the corresponding assay system from O-2 interference. Moreover, GeO2 nanozymes are white, thereby eliminating the color interference of the nanozymes themselves in nanozymes-based colorimetric assay. Interestingly, compared with other metal oxides, GeO2 nanozymes are easily decomposed by thiocholine, acetylcholinesterase (AChE)-catalyzed hydrolysate, which triggers an ultrasensitive and anti-interference organophosphate pesticides assay process based on the irreversible inhibition of AChE. The proposed strategy about finding nanozymes with single activity without interference color will open avenues for improving the performance of colorimetric analysis systems based on nanozymes.