| With the development of human society, people’s living standards become higher and higher. More and more people are with diabetes. Therefore, in order to prevent the happening of the disease, it is of significance to detect glucose and hydrogen peroxide. For a long time, according to the study of human metabolism, some function of enzymes in the body was found. Some simple traditional enzymes have been synthesized. However, these enzymes are expensive, bad stability and have other shortcomings. In recent years, with the development of nano-materials, researchers focused on the seach and design of new nano-materials with peroxidase-like activity. Much effort focuses on the futher enhancement of peroxidase-mimetic actvity. In this dissertation, we focuse on the synthesis of iron-containing composite materials with high catalytic activity, including reduced graphene oxide-iron nanoparticles(RGO-INs) and metal-organic framework(MOFs, MIL-53(Fe)), which exhibit the inherent peroxidase-like activity. In the presence of H2O2, RGO-INs and MIL-53(Fe) can catalyze the oxidation of peroxidase substrates, such as TMB, OPD, THB to produce a typical color reaction, which are used as a biosensor for the detection of hydrogen peroxide, glucose, and ascorbic acid at a low detection limit. Meanwhile, we also study the synthesis of the other non-iron-based nanomaterials, such as Bi OBr semiconductor and demonstrate its highly efficient peroxidase-like catalytic activity for the detection some small biological molecules. The main content is descibed as the following:1. We present the synthesis of the reduced graphene oxide(RGO)-iron nanoparticles(INs), RGO-INs, by a facile iron-self-catalysis process at room temperature, which can be utilized as the highly active and cost-effective enzyme-mimetic catalysts. In the presence of hydrogen peroxide, RGO-INs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine(TMB) to produce a typical color reaction. RGO-INs show better catalytic performance than that of the individual components, indicating a synergistic effect between the components in the composites. On the basis of peroxidase activity of RGO-INs, a visual colorimetric method for the detection of H2O2 and glucose is established. This method has an advantage of low cost, easy operation, high sensitivity and low detection limit, which more efficient than other nanomaterials. The linear ranges for H2O2 and glucose detection were 0.76 to 47 μM and 2.0 to 30 μM, with corresponding detection limits of 0.2 and 0.8 μM, respectively. As mimetic peroxidase, the RGO-INs has potential applications in biosensing.2. Metal–organic framework MIL-53(Fe) was synthesized by a facile one-pot solvothermal method using DMF as solvent, which was mainly consisted of pseudo sphere-like aggregates with a size of 200-800 nm. In the presence of H2O2, MIL-53(Fe) can catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine(TMB) and o-phenylenediamine(OPD), showing highly efficient peroxidase activity. Based on this performance, the MIL-53(Fe) provide an efficient platform for colorimetric detection of H2O2. In addition, based on AA-induced inhibition of the peroxidase-like activity of MIL-53(Fe), a simple colorimetric method for the detection of ascorbic acid(AA) was realized. In addition, MIL-53(Fe) shows efficient catalytic activity and good stability compared with other nanomaterials.3. Layer-structured Bi OBr was synthesized by a solvothermal method and demonstrated to be a novel biomimetic catalyst possessing highly efficient intrinsic peroxidase-like activity. In dark, the Bi OBr presented high catalytic activity as well. On the basis of such catalytic performance, a method for the colorimetric detection of hydrogen peroxide, glucose, and ascorbic acid(AA) was established. This method is simple, convenient, and easy operation. |
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