Selective Separation Of Pepsin Based On Functional Magnetic Materials

Protein is the basic constituent of living organisms and plays an important role in life activities.Protein analysis studies have received extensive attention.The development of efficient and rapid separation techniques is of great significance for the advancement of proteins.Traditional methods such as filtration,precipitation,and dialysis lack selectivity for protein separation,while liquid chromatography and electrophoresis require complex sample processing.Magnetic nanoparticles have the characteristics of large specific surface area,high surface activity and rapid response to external magnetic fields,and have good application potential in the field of protein separation.Magnetic nanoparticles are easy to modify due to their high surface activity,and appropriate surface modifications can selectively recognize binding proteins.Based on the strong hydrogen bond between glycohydroxyl group and several amino acid residues(with amino,carboxyl,hydroxyl and other active groups)on protein,and the different charge of protein under different pH value,this research mainly prepared the functional magnetic nano-materials of glycomonomers and positively charged monomers to research the selective adsorption of pepsin by the materials.Firstly,the ferroferric oxide nanoparticles were prepared by the solvothermal method;the surface of the ferroferric oxide was coated with a layer of silica by the Stober method using tetraethoxysilane as the silicon source;The[2-(Methacryloyloxy)ethyl]trimethylammonium chloride and Glycosyloxyethyl methacrylate are functional monomers which are freely polymerized with allyltriethoxysilane in the presence of the initiator ammonium persulfate.Then the polymer formed Si-O-Si bond through the reaction of silane coupling agent and silicon hydroxyl,and then it was connected to the magnetic nanoparticles coated with silica to obtain functional magnetic nanomaterials.The functionalized magnetic nanomaterials were characterized by transmission electron microscope(TEM),fourier transform infrared spectroscopy(FT-IR),thermogravimetry(TGA)and magnetic vibrating sample magnetometer(VSM).The results show that the prepared material has a size of about 300 nm,good dispersion and superparamagnetism,which meets the requirements of magnetic separation.The adsorption isotherm experiment of showed that the adsorption capacity of functionalized magnetic material for pepsin increases with the increase of pepsin concentration,and the adsorption capacity was 250 mg/g.The experimental results of adsorption kinetics show that the functionalized magnetic material has a fast binding kinetics for pepsin,and the adsorption equilibrium can be achieved in 5 min.Functionalized magnetic materials are capable of selectively identifying isolated target proteins from protein mixed samples.This has good application potential for protein separation.