MnO2 nanozyme@persistent luminescent nanoparticles for dual-modality glucose detection†

Abstract

High blood glucose levels can cause diabetes, which in turn leads to various diseases, such as cardiovascular and cerebrovascular diseases, so monitoring of blood glucose levels is urgent. Here, we report persistent luminescent nanoparticles (PLNPs), Zn_1.1Cu_0.001In_0.0009Ga_1.8Ge_0.1O₄ (ZCIGG), to avoid interference from background fluorescence in conventional optical sensing, surface-loaded with MnO₂ nanozymes for bimodal glucose detection. The two detection modes are validated with each other and are suitable for a wide range of situations. To this end, ZCIGG was prepared with afterglow emission at 500 nm and then integrated with MnO₂ nanosheets through a dissolved oxygen strategy. MnO₂ shows broad absorption and quenches the phosphorescence of ZCIGG. MnO₂ acts as a peroxidase-like enzyme to catalyze an H₂O₂-tetramethylbenzidine (TMB) reaction for the colorimetric detection of glucose, in the presence of glucose oxidase (GOx); MnO₂ also acts as an oxidase to catalyze the oxidation of H₂O₂ to produce Mn²⁺ and recover afterglow emission for the phosphorescent detection of glucose. Density functional theory and microscopic kinetic modelling provide a theoretical analysis of the catalytic mechanism of MnO₂ nanozymes for dual-modality detection. We also developed a mobile-phone-based intelligent analysis platform using the Python algorithm for the convenient on-site colorimetric and phosphorescent dual-detection of glucose.