(20h) Hemin Metal-Organic Framework As Artificial Enzyme for Glucose Detection

Researchers have made a lot of effort to extend the natural enzymes to enzyme mimetics with high substrate specificity and high catalytic efficiency under mild conditions due that natural enzymes suffer from many serious disadvantages such as high costs of preparation, purification and storage and easily affected their activity by environmental conditions including pH value, temperature and inhibitors. Hemin which is the active center of the heme-protein family including cytochromes, peroxidases, myoglobins, and hemoglobins, can catalyze a variety of oxidation reactions like peroxidase enzymes. Howerver, it suffers from limited lifetime catalytic activity because of its oxidative self-degradation and molecular aggregation to inactive dimers in aqueous solution. A promising approach to solve this problem is to immobilize hemin to high surface area materials. In this paper, we showed a composite material which was prepared using an amino-containing MOF (MIL-101(Al)-NH2) as a new type of host matrix material to anchor hemin and simulate the peptidic microenvironment in the native peroxidase. The composite material was characterized by XRD, SEM, EDS, FT-IR and BET. It has been demonstrated to exhibit peroxidase-like activity through catalytic oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue-colored solution. Under the optimal conditions, the absorbance at 652 nm is well linearly correlated with the concentration H2O2 from 5.0×10-6 mol/L to 2.0×10-4 mol/L with a detection limit of 2.0×10-6 mol/L (R2 = 0.9939). More importantly, a sensitive and selective method for glucose detection was developed using the as-prepared mimetic peroxidase as catalyst with the help of glucose oxidase (GOx). It was observed to have a linear range from 5.0 μM to 500 μM. To our best knowledge, this is the first time using MOF-artificial enzyme in the application of glucose detection. This work enlightens us a new method for preparing biomimetic catalyst and extends metal-organic frameworks functionality to biosensor applications.