Rational Design of Light-Responsive Nanozyme with Reversible Inhibitory Function for Colorimetric Sensing of Diclofenac Sodium

Unraveling the reversible inhibition mechanisms of nanozymes is critical; however, current research predominantly relies on metal-containing materials, where strong metal-inhibitor interactions often induce irreversible adsorption, complicating the study of reversible inhibition. By comparison, nonmetallic porous materials have emerged as promising candidates for exploring reversible nanozyme inhibition owing their nonmetallic nature, high adsorption capacity, and low mass transfer resistance. Herein, we employed a nonmetallic porous light-responsive nanozyme (denoted TTBT·Cl) and diclofenac sodium (DS) as a model system to systematically investigate reversible inhibition mechanisms. TTBT·Cl not only exhibited high adsorption capacity for oxygen substrates and facilitated mass transfer of both substrate and inhibitor, but also displayed excellent light-responsive oxidase-like activity. Through comprehensive characterization and experimental analyses, the photocatalytic and uncompetitive inhibition mechanisms of the TTBT·Cl nanozyme were clarified. To overcome this inhibitory effect, a selective and sensitive colorimetric platform was developed for DS detection. This study offers a conceptual framework for exploring inhibition mechanisms in other nanozyme systems and has the potential to broaden the application scope of nanozyme-based biosensing.