Interactions Of Bovine Serum Albumin With Metallic Biomaterials And Its Surface Modification

The proteins can spontaneously and rapidly adsorb on the surfaces of biomaterials to form a protein film as biomaterials expose to body fluid.Protein adsorption as the first step of the interactions between biomaterials and the physiological environment is hence one of the most important aspects to evaluate the biocompatibility of biomaterials.In this paper,the adsorption of protein on the metallic biomaterials with an inert surface as well as an active surface was researched,respectively.The bovine serum albumin(BSA)was chosen as the model protein.The adsorption of BSA on cobalt-based alloy of MP35 N and magnesium were studied by means of confocal laser scanning microscope(LSCM).And the effects of protein adsorption on the surface structure and properties of metallic biomaterials were investigated by different techniques such as scanning electron microscopy(SEM),X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy and so on.Then the surface modification of magnesium alloy AZ31 was conducted by using of polycarbonate(PC)and poly(lactic acid)(PLA)combined with micro-arc oxidation technology(MAO)to obtain a composite film.The surface structureof the composite film was characterized by means of SEM,contact angle analyzer,etc.The corrosion resistance of the modified AZ31 was measured by means of potentiodynamic polarization curve.Its anti-fouling performance and antibacterial properties were also studied.The results are shown as follows:1)As the concentration of BSA increases,the adsorption of protein on the surface of MP35 N increases.The structure of adsorbed protein layers gradually changes from a monolayer with the surface of the substrate partially and/or completely covered by proteins to a multilayer structure.BSA induces a significant enrichment of chromium in the surface oxide of MP35 N,while the content of oxidized iron is significantly decreased.Protein adsorption generally enhances the metal release from MP35 N,but the effect for different metals is different.Protein adsorption reduces the corrosion resistance of MP35 N,and the extent of the reduction is related to the structure of adsorbed protein layers.In addition,protein adsorption is beneficial to the adhesion of osteoblasts on the surface of MP35 N,especially a protein multilayer formed on the surface.2)Both protein concentration and duration time effect on the adsorption of BSA on magnesium surfaces.Protein adsorption effects on the surface structure of magnesium and vice versa.As the duration time increases,the surface roughness of magnesium increases and the thickness of the protein layer also increases.At the same time,the complexation of proteins with magnesium surface most likely accelerates the occurrence of pitting corrosion,resulting appearance of a large amount of corrosion products on the surface.The maincomponent is magnesium oxide.Protein adsorption generally reduces the corrosion resistance of the magnesium surface,and the reduction most likely linkto the structure of adsorbed protein layers.Surface hydrophobicity of the substrate and it also prevents the adsorption of proteins.In addition,surface modified AZ31 shows good activity against Staphylococcus aureus.So it can be expected that the surface modified AZ31 with multiple functions could have great potential in the medical field.3)Surface hydrophobicity of the substratesurface hydrophobicity of the substrate and it also prevents the adsorption of proteins.In addition,surface modified AZ31 shows good activity against Staphylococcus aureus.So it can be expected that the surface modified AZ31 with multiple functions could have great potential in the medical field.