Modulation Of Pre-adsorbed Proteins On TiO₂ Surfaces Using UV Irradiation To Construct Biocompatible Surfaces

Protein as the substance foundation of life has multiple functions such as immunity,catalysis,transportation,coordination,and control of growth and differentiation.The adsorption behavior of protein on the surface of materials is not only the key factor of the biological performance of materials in vivo,but also the theoretical basis of understanding of cell-material interaction.Therefore,regulating the adsorption behavior of protein on the surface of materials has become a research hotspot.UV irradiating TiO₂（as a well-known photocatalytic material）,can produce a large number of active free radicals and regulate the structure of protein adsorbed on the surface.The previous research of our group found that these active substances can partially desorb the protein adsorbed on the TiO₂ surface.On this basis,the pre-adsorbed albumin and fibrinogen on the surface of TiO₂ were taken as the research objects in this paper.The composition,morphology,structure,charge,surface energy of the remaining protein on TiO₂ after UV irradiation was studied,and the effect of the remaining proteins on the adhesion of platelets,cells and bacteria,and the histocompatibility in vivo were further studied.The main results were shown below:The results of Zeta potential,water contact Angle（WCA）,X-ray photoelectron spectroscopy（XPS）and fourier transform infrared spectroscopy（FT-IR）showed that the surface of TiO₂-BSA（FGN）-UV became more hydrophilic,the negative charge of surface was increased and the secondary structure of the remaining protein on the surface was changed.A series of blood compatibility experiments showed that the TiO₂ surface pre-adsorbed with protein had good anticoagulant effect after UV irradiation.In addition,the regulation of platelet adhesion behavior on the micrometer scale was realized by mask UV irradiation.Through static cells adhesion in vitro,it was found that the TiO₂ surface pre-adsorbed with protein promoted cells adhesion after UV irradiation,and the regulation of endothelial cells adhesion behavior on micrometer scale was realized by mask UV irradiation.By controlling the content of fetal bovine serum in the culture medium,it was found that the adhesion behavior of Staphylococcus aureus was related to the selective adsorption of proteins in serum.Finally,through in vivo experiments,it was found that the TiO₂ adsorbed with bovine serum albumin（TiO₂-BSA）significantly inhibited tissue proliferation,and there were numerous hyperplastic tissues and smooth muscle cells around the pre-adsorbed protein TiO₂ surface after UV irradiation（TiO₂-BSA（FGN）-UV）.In summary,the protein surface after UV irradiation inhibited the adhesion of platelets and promoted the adhesion of cells.The realization of these functions was related to the specific adsorption of other proteins on the surface.This modified surface has a good application prospect in the fields of blood contact materials and bone implant materials.