Study On Preparation And Characterization Of Carriers For Protein Immobilization And Separation

Over the last decade,protein immobilization and separation technology has been received high attention and had made some progress.There are more challenges in the process of protein immobilization and separation because of the complexity of its components,the flexibility and variability of its space structure.The methods of protein immobilization and separation could be divided into two ways macroscopically:physical method and chemical method.How to choose and design an adaptable and feasible method to immobilize and separate protein is the most difficult task in the project of protein immobilization and separation.On the aspect of carriers for protein immobilization,in this article,we select the polyurethane(PU) surface as the original basic material.Firstly,the PU surfaces were stepwise modified and then the chelator head(quinolin-8-ol,HQ) was grafted on PU surfaces.Finally,the metal chelating layer was formed on the PU surfaces through the coordination interaction between chelator and metal ions.The process involved the introduction of a poly(ethylene glycol)(PEG) layer to shield the PU substrate surface against nonspecific protein adsorption,the grafting of HQ provided a good chelator for forming unsaturated complex with metal ions.The properties of modified surfaces were analyzed through X-ray Photoelectron Spectroscopy(XPS), the testing result indicated that PEG and HQ has been grafted on PU surfaces successfully,metal ions and HQ had been formed expected complex.The protein adsorption capacities of the surfaces were tested through protein adsorption experiments,the testing results indicated that Ni²⁺ chelating PU surface had more protein adsorption capacity than other metal ions,protein adsorption capacity of Ni²⁺ chelating surface increased to 2.14 and 20.4 times than before chelating and only PEG grafted surfaces,respectively.Protein bioactivity testing results indicated that Ni²⁺ chelating surfaces not only had the priority immobilizing protein stably but also can keep the natural activity of immobilized protein.On the aspect of carriers for protein separation,in this study,a molecular imprinting polymer was formed using bovine serum albumin as "print" molecule, epoxy chloropropane as crosslinker,and the coordination compound of chitosan and metal ion as functional matrix.The morphologies of the molecular imprinting polymer were characterized by environmental scanning electron microscope,and the selective adsorption and separation effect was evaluated by protein adsorption experiment.The analytical results showed that the imprinted polymer had good selectivity to bovine serum albumin.The bovine serum albumin adsorption of the molecular imprinting polymer was 21.9 times of the non-imprinted polymer.The imprinted polymer showed good selective adsorption and separation ability to the bovine serum albumin.