Sensing array based on imidazole-regulated Cu@MOFs nanozymes with enhanced laccase-like activity for the discrimination of phenolic pollutants

Background: Phenolic pollutants with high toxicity and low biodegradability can disrupt environmental balance and severely affect human health, whereas existing methods are difficult to implement the rapid and high- throughput detection of multiple phenolic pollutants. Results: Herein, we developed a four-dimensional colorimetric sensor array based on imidazole-modulated Cu@MOFs for distinguishing and determining phenolic pollutants. Wherein, four Cu@MOFs (ATP@Cu, ADP@Cu, AMP@Cu, and GMP@Cu) nanozyme with laccase-like activity were firstly prepared, and a novel strategy of imidazole-containing molecules-regulated was proposed to improve the laccase-like activity of Cu@MOFs nanozymes. Interestingly, imidazole (IM) exhibited the strongest enhancing effects on the laccase-like activity of the four Cu@MOFs by accelerating electron transfer on the surface of laccase nanozymes and producing more reactive oxygen species. Subsequently, by using Cu@MOFs@IM as the recognition elements of the sensor array, a colorimetric sensor array based on imidazole-modulated Cu@MOFs was developed, and differentiation and classification of phenolic pollutants were carried out using LDA and HCA methods. More importantly, the proposed sensor array could accomplish the identification of 6 phenolic pollutants and their mixtures. Significance: Additionally, the designed sensor array was applied to identify these phenolic pollutants in real water samples, further highlighting the potentials for assessing water pollution.