Study On The Selective Adsorption Of Proteins On TiO₂ Nanoparticles With Surface Epoxide Modification

The nanomaterials have been wildly applied in the biomedical area with the development of nanoscience and nanotechnology, which play important role in many fields, such as disease diagnosis and treatment, tissue repair and proteins separation.. Nano-TiO2, as a biologically inert material, has good biocompatibility. In addition, the surface functionalization of TiO2 can be achieved by the surface chemical reactions between its surface hydroxyl groups and organic molecules. Furthermore, the research on the special adsorption of proteins on some functionalized nanomaterials has important theoretical significance and application valuec in the field of protein adsorption separation.The TiO2 nanoparticles were prepared by improved hydrothermal method, and then the silane (KH560) with epoxy group was used to modify the Tio2 nanoparticles. Some means, such as TEM, XRD, TG-DSC, and FT-IR were used to character the KH560/TiO2 nanoparticles. The results showed that the KH560 molecules were successfully combined on the surface of TiO2 nanoparticles. The average size of pure TiO2 nanoparticles was about 7 nm, which was became bigger after KH560 modification because of the soft agglomeration. The KH560/TiO2 was with anatase structure, and the amount of bonding KH560 molecules was about 37.2% based on the TG analysis.The KH560/TiO2 nanoparticles were used in the adsorption experiments of bovine hemoglobin (BHb) and bovine serum albumin (BSA). The effects of different conditions on the adsorption capacity were studied systematically, and the optimum adsorption conditions were determined, which were as follows:pH=8, the initial concentration of BHb was 150 μg-mL-1, TiO2 amont was 0.8 mg-mL-1 and the contact time was 80 min. In contrary, the KH560/TiO2 nanoparticles almost did not adsorb 1BSA, which may be caused by the nature of BS A and larger steric hindrance.For the adsorption of BHb on KH560/TiO2 nanoparticles, the higher R2 (=0.996) values confirmed that the applicability of pseudo-second-order kinetic model was more suitable than pseudo-first-order model. The adsorption thermodynamics present that the values of △Hθ,△Sθ and △Gθ were less than 0, which indicated that the adsorption process of BHb on KH560/TiO2 can occur spontaneously. The IR results under different pH values showed that the chemical adsorption was occurred through the chemical interaction of epoxy groups and the amino of BHb under alkaline condition.