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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), Zn1.1Cu0.001In0.0009Ga1.8Ge0.1O4 (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. [ABSTRACT FROM AUTHOR]

Copper in vegetables can enter the human body, and excessive copper may cause uncomfortable symptoms; thus, it is urgent to test copper ions for safety concerns. Herein, we prepared Zn2GeO4:Mn2+,In3+ (ZGO:Mn,In) persistent luminescent nanoparticles (PLNPs) and then grafted glutathione for the determination of copper ions. ZGO:Mn,In was prepared by doping In3+ in ZGO:Mn to improve the emission at 532 nm under excitation at 258 nm. The doping amount, temperature, time, and pH were carefully optimized for a stronger emission intensity than ZGO:Mn. The fractional densities and energy band gaps were calculated by density functional theory, revealing the excitation enhancement mechanism of ZGO:Mn,In. The surface of ZGO:Mn,In was modified with carboxyl groups for linking glutathione to specially identify Cu2+ ions. The identification resulted in the aggregation-induced quenching of PLNPs' emission. Thus, the sensor exhibited good selectivity for copper ions, and the composite was successfully applied to the detection of copper ions in serum and vegetable samples. [ABSTRACT FROM AUTHOR]