Preparation Of Novel Protein-inorganic Salt Hybrid Nanocomposites And Their Applications

Protein-inorganic salt hybrid nanocomposites,owing to their controllable morphology,large specific surface area and good biocompatibility,have drawn more interest recent years.Immobilized protein on inorganic salt have some advantages such as excellent biological activity,stability and reusability.In light of these advantages of the hybrid nanocomposites,a series of protein-inorganic hybrid nanocomposites were synthesized by a novel approach by using different protein and inorganic components,respectively.Significantly,the resultant protein-inorganic hybrid nanocomposites can be applied as immobilized enzyme reactor and colorimetric platform for highly efficient protein digestion and fast visual detection of small molecules.The contents of this paper include:In chapter 1,a general review of organic-inorganic hybrid nanocomposites was systematically introducted,specially focusing on description of immobilized methods and the supports of protein,containing the introduction of protein immolobilizing on inorganic salt matrix by self-assembly.Besides,the significance and content of this paper were also briefly presented.In chapter 2,this work reported a facile approach for the synthesis of trypsin-inorganic hybrid nanoflowers by self-assembly of trypsin and nickel phosphate(Ni3(PO4)2·8H2O)in aqueous solution.The hybrid nanoflowers were characterized by Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),Energy Dispersive Spectrometer(EDS),X-ray powder diffraction(XRD).The enzymatic activity of immobilized trypsin was studied by monitoring the esterification reaction of N-?-benzoyl-L-arginine ethyl ester(BAEE),and the results showed 207%enhancement under the optimal conditions.The performance of hybrid nanoflowers was further demonstrated by digesting bovine serum albumin(BSA)and human serum albumin(HSA),with a stringent threshod for unambiguous identification of these digests,the yielding sequence coverage for nanoflower-based digestion were the same as those obtained with the free enzyme.Whereas the digestion time in the former case was only 1 min,about 1/720 of that performed in the latter case(12 h).Furthermore,the hybrid nanoflowers were applicable to the digestion of human serum,showing great promise for proteome research.In addition,the preparation of hybrid nanocomposites based on Mg2+,Ba2+,Zn2+ and Co2+ as the inorganic component were also carried out for the research of protein immolobilized principle.In chapter 3,this work developed a facile approach for the fabrication of protein-immobilized metal organic frame(ZIF-8@BHb)by using bovine hemoglobin(BHb)as the organic component and zeolitic imidazolate framework-8(ZIF-8)as the inorganic component,respectively.The peroxidase-like catalytic activity of BHb immobilized in ZIF-8@BHb was evaluated based on the principle of BHb catalyzing the oxidation of 3,3',5,5'-Tetramethylbenzidine(TMB).The results showed that 423%enhancement of activity in ZIF-8@BHb could be achieved compared with the free BHb in solution.Taking advantages of the unique structure of ZIF-8@BHb with catalytic property,a colorimetric biosensing platform was newly designed and applied for fast and sensitive detection of H2O2 and phenol.The detection limits as low as 1.0?M for each analyte obtained by naked-eye visualization,which meet well the requirements of detection of both analytes in clinical diagnosis and environmental water.The proposed method has been successfully applied to the analysis of low-level H2O2 in cell and phenol in sewage,respectively.These primary results demonstrate that the hybrid nanocomposites have a great potential for applications in biomedical and environmental chemistry.