TiO(2)-In-MIL-101(Cr) with Visible Light-Induced Peroxidase Activity for Colorimetric Detection of Blood Glucose

[Image: see text] In this work, metal–organic framework MIL-101(Cr) with regular morphology, stable structure, and good dispersion was prepared by the hydrothermal method. MIL-101(Cr) has two different sizes of pores, but after TiO(2) nanoparticles (NPs) were in situ prepared, the two pores disappear. The result demonstrates that TiO(2) NPs were located in the pores of MIL-101(Cr). TiO(2)-decorated MIL-101(Cr) forms an inside type II heterojunction and the band gap energy is narrowed, which can promote electron–hole separation and enhance the light absorption. Therefore, the heterojunction shows a high visible light-induced peroxidase-like activity. Kinetic studies exhibit that the K(m) value of TiO(2)-in-MIL-101(Cr) to TMB is 0.17 mM, and the affinity of TiO(2)-in-MIL-101(Cr) is higher than that of natural horseradish peroxidase (HRP). Then, a “turn-on” colorimetric assay based on TiO(2)-in-MIL-101(Cr) was constructed for the detection of blood glucose. The detection range is 1–100 μM (R(2) = 0.9950) with a limit of detection (LOD) of 1.17 μM. Compared with the clinical method, the constructed colorimetric method has accurate and reliable results for the clinical detection. The anti-interference experiment confirms that the method has high selectivity to glucose.