The Adsorption Behavior Of BSA(LSZ) On The Surface Of The Material And The Effect Of Its Primary Structure On The Mineralization Process

Biomineralization occurs on the surface of the material.The surface properties of the material and the solution environment will have a regulatory effect on the number,arrangement,and structure of the protein layers on the surface,which in turn affect the mineralized crystals.Understanding the effects of biomaterial surface properties and solution environment on protein adsorption behavior is of great significance for a better understanding of the biomineralization process;After the bone repair material is implanted into the body,the protein adsorbs on its surface and participates in biomineralization to form bone-like apatite.Protein primary and secondary structure and molecular arrangement of protein layer have specific regulation on biomineralization,but its mechanism needs further study.In this thesis,electrophoretic deposition was used to prepare hydroxyapatite?HA?coatings with different morphologies on the surface of materials.The quartz crystal microbalance?QCM-D?technique was used to investigate the adsorption behavior of proteins with different qualities on the surface of HA coatings with different morphologies.At the same time,the influence of environmental factors on the solution was also investigated.The regulation of materials surfaces mineralization by different groups in the primary structure of the protein was investigated?due to time,the regulation of the secondary structure of the protein and the molecular arrangement of the protein layer on biomineralization is not covered in the paper.?.The research results and conclusions are as follows:Electrophoretic deposition methods were used to prepare HA coatings with different particle sizes or roughness,and the influences of surface morphologies on differently charged Bovine serum protein?BSA?and lysozyme?LSZ?adsorption were investigated.The results show that for single-layer adsorption,HA coatings with smaller deposited particles are better for adsorbing negatively charged BSA on the surface,and HA coatings with larger deposited particles are better for adsorbing positively charged LSZ on the surface.There is a competitive relationship between the effects of the deposited particles size and roughness.The larger the roughness,the better the protein adsorption,but when the size of the deposited particles is different,the effect of the particle size of the deposited particles is dominant,and the effect of roughness is not significant at this time.The effects of solution pH and calcium-phosphorus ion concentration on BSA protein adsorption on material surfaces and their effects on secondary structure were investigated.It was found that:1)Under the condition of salt balance,the pH has a different effect on the quality,structure and protein conformation of the adsorbed protein layer on the surface of different substrates?Au/Si O₂/HA?in the pH range of 6.5?8.7.2)At the same pH,the presence of low concentration of Ca²⁺can promote the adsorption of BSA on the surface of Au,while the higher concentration is not conducive to the adsorption of BSA,and the presence of PO₄^3-is not conducive to the adsorption of BSA on the surface of Au.3)When pH 6.9 or pH 7.9,the?-helix and?-sheet of BSA protein will decrease.Concentration changes in the range of 0.005?0.02M Ca²⁺or 0.008?0.032M PO₄^3-had almost no effect on the secondary structure of BSA.The poly?lysine??PL?side chain was modified by acylation reaction.The regulation of HA surface mineralization by amino acid polymers with different groups in the side chain was investigated,by using simulated body fluid immersion and QCM-D technology.It was found that the PL which has hydrophilic-NH₂ in the side chain had the effect of inhibiting and then promoting the mineralization of HA surface,and PL-CH₃ which has hydrophobic-CH₃ in the side chain has a significant inhibitory effect on the growth of mineralized crystals on the surface of HA.They have little effect on mineralization morphology.In the mineralization process containing PL or PL-CH₃,the phases of calcium hydrogen phosphate hydroxide appear in the initial stage.