Substrate-Driven Coenzyme Activating Oxidase-Like Activity of Copper-Based Nanozymes for Robust Profiling of Sulfonamides

Nanozymes offer significant advantages, including high stability, straightforward synthesis, and low cost, positioning them as viable alternatives to natural enzymes. However, the limited variety and specificity of nanozymes have been a persistent challenge. In this study, we developed a copper metal-organic framework material (Cu-MOF) using poly(acrylic acid) nanoparticles (PAA NPs) as a structural core. We innovatively discovered that sulfonamides (SAs) can function as coenzymes to activate the oxidase-like activity of Cu-MOF. Through multiple experimental approaches, the mechanism underlying the coenzyme-like function of SAs was investigated. The high affinity between SAs and Cu-based nanozymes serves as the substrate-driven foundation, promoting the generation of multiple reactive oxygen species and collaborating with electron transfer processes to accomplish catalytic oxidation. This discovery provides insights for broadening nanozyme substrate diversity and enhancing nanozyme specificity. Given that SAs are among the most widely used antibiotics, their environmental implications necessitate careful consideration. To address this, we concurrently designed a colorimetric sensing system for SAs based on the Cu-MOF nanozyme, integrating it with smartphone camera functionality to enable RGB detection. Additionally, by applying principal component analysis (PCA) to the RGB data, we achieved simultaneous detection and identification of multiple SAs, even in mixed samples. The present study proposes a substrate-driven nanozyme coenzyme theory, also highlights the potential of smartphone-integrated colorimetric sensors for effective visualization and high-throughput detection, thereby broadening the application scope of nanozyme.