A novel and sensitive microneedle array platform for visual detection of glucose based on Zr-MOF@Pt nanozyme with peroxidase-like activity

The level of glucose, one of the body's energy-providing substances, is closely related to many diseases. Therefore, it remains a challenge to develop platform that can satisfy both the need for accurate detection of glucose for clinical diagnosis as well as device-free and efficient on-site monitoring of blood glucose. Herein, we synthesized Zr-MOFs@Pt nanocomposites for the first time. The peroxidase-like activity of Zr-MOFs@Pt was greatly enhanced two times compared with Zr-MOFs, due to the synergistic effect of Pt nanoparticles that was in situ growing in Zr-MOFs. Hydrogen peroxide was generated from glucose with the catalysis of glucose oxidase (GOx). H2O2 was decomposed by Zr-MOFs@Pt to produce free radical, which could oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to generate blue oxTMB, and could be utilized for colorimetric sensing of glucose. By crosslinking, TMB and PVA hydrogel matrix formed the microneedle patch display layer, and PVA as well as GOx composed the tip of the needle, the sensing system was developed to hydrogel microneedles array for detection of glucose. When the tip of the needle was inserted into a solution containing glucose, it reacted with GOx in the tip sector to produce H2O2. The H2O2 would react with Zr-MOFs@Pt in the display layer to produce free radicals, and further oxidize TMB causing the display layer to exhibit blue color. This work provides a new approach for designing device-free sensing platforms for glucose monitoring, which also offers great potential for development of microneedle analytical devices.