Ultrasmall phosphatase-mimicking nanoceria with slight self-colour for nonredox nanozyme-based colorimetric sensing

Nanozyme-based colorimetric sensing has attracted significant interest in recent years, and a number of redox-type nanozyme-based colorimetric sensors based on peroxidase and oxidase mimics have been reported. However, conventional redox-type nanozyme-based colorimetric sensing is affected by interference from the endogenous reductants present in actual samples. Herein, we describe the development of a homogeneous nonredox-type nanozyme-based colorimetric sensor that exploits the intrinsic phosphatase-like activity of CeO₂. Specifically, colorimetric detection platforms for fluoride ions, zearalenone, and hydrogen peroxide were constructed based on activity inhibition, aptamer-assisted gate control, and plasmonic nanoparticle growth, respectively. Thus, this study reports a versatile route for constructing nonredox nanozyme-based colorimetric sensors that are not affected by interference from endogenous reductants and are thus highly promising for use in food safety and bioassay applications.