Synthesis of Mn-Prussian blue analogues with multi-enzyme activity and related application for alcohol detection

Manganese-contained Prussian blue analogues (Mn-PBAs) have a rigid and open 3D framework and adjustable redox potential, coupled with nontoxic nature, they could be effectively applied in various medicinal and biomedical fields. In this study, we reported the nanozyme activity of Mn-PBA nanoparticles. It was found that Mn-PBA nanoparticles possess peroxidase (POD)-, urate oxidase (UOD)- and catalase (CAT)-like enzymes, and this multi-enzyme activity is pH-switchable. The working mechanism of Mn-PBA nanoparticles mimicking peroxidase to oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) was pursued. In this process, Mn-PBA nanoparticles accelerate the decomposition of H2O2 into •OH, so that •OH catalyzes the oxidation of TMB. Based on the color reaction and the cascade reaction, we constructed a platform that utilizes Mn-PBA nanoparticles to detect alcohol concentration. This platform has a wide detection range and high detection accuracy, as well as excellent detection specificity. For example, 25 μM-2.5 mM concentration of alcohol can be measured accurately with a good linearity overall, and the limit of detection of the alcohol concentration can reach low to 3.17 μM. These studies prove that the application of Mn-PBA nanoparticles in biomedicine and detection has bright prospects.