A nanosized metal-organic framework of Fe-MIL-88NH(2) as a novel peroxidase mimic used for colorimetric detection of glucose

In this paper, a nanosized porous metal-organic framework, Fe-MIL-88NH(2), was facilely prepared with a uniform octahedral shape by the addition of acetic acid, and for the first time was demonstrated to possess intrinsic peroxidase-like activity. Kinetic analysis and electron spin resonance measurements indicated that the catalytic behavior was consistent with typical Michaelis-Menten kinetics and follows a ping-pong mechanism. As a novel peroxidase mimic material, Fe-MIL-88NH(2) shows the advantages of high catalytic efficiency, ultrahigh stability and high biocompatibility in aqueous medium compared with natural enzymes and other peroxidase nanomimetics. Here, Fe-MIL-88NH(2) was used to quickly catalyze oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a colored product, which provided a simple, sensitive and selective method for the colorimetric detection of glucose. Glucose could be linearly detected in the range from 2.0 x 10(-6) to 3.0 x 10(-4) M with a detection limit of 4.8 x 10(-7) M, and the color variation for glucose response was also obvious by visual observation at concentrations as low as 2.0 x 10(-6) M. More importantly, the colorimetric method could be successfully applied to the determination of glucose in diluted serum samples.