Research On The Facile Synthesis Of Au@TiO₂ Nanoparticle And Its Biomedical Applications

Benefiting from the Surface Plasmon Resonance Effect(SPR)of noble metals,the absorption wavelength of Au@TiO₂nanoparticles could be extended to visible light and the better inhibition of the photogenerated electron-hole pairs recombination owing to the construction of Schottky heterojunction facilitates the improvement of their photocatalytic performance.The reactive oxygen radical species(ROS)produced by Au@TiO₂nanocomposite under visible light irradiation could destroy the biological structures such as DNA and cell membrane which promise their applications in photocatalytic sterilization.Meanwhile,Au@TiO₂nanocomposite also possess the responsibility to X-ray,which could be utilized for constructing radiotherapy enhancement nanoplatforms.The commonly-used preparation methods for Au@TiO₂nanocomposite always require harsh conditions and extra experimental devices with the shortcomings such as uneven loading and inferior reproducibility.Therefore,developing a highly-efficient,mild and controllable preparation method of Au@TiO₂nanomaterials is highly required.More specifically the key points of our study are:1.We developed one facile synthesis method for Au@TiO₂nanospheres.Chloroauric acid was rapidly reduced to Au nanoparticles with a particle size of about10-20 nm at room temperature and uniformly deposited on TiO₂substrates with polyvinylpyrrolidone and ascorbic acid as protective agent and reductive agent,respectively.The Au@TiO₂nanospheres prepared by this method maintains good morphology,dispersion and stability,as well as excellent photocatalytic free radical generation efficiency,verified by the corresponding characterization.2.We achieved excellent visible light-induced insitu antibacterial performance based on the Au@TiO₂nanospheres prepared above.The nanospheres maintained high adhesion towards bacterial surface which guaranteed the insitu generation of ROS,verified by series of biological characterization.It showed excellent bacteriostatic effect on both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)under low dose concentration.3.We designed and synthesized the three-layer core-shell TiO₂/Au@CeO₂nanoparticles and achieved the excellent synergistic antitumor performance for hypoxia condition relief and radiotherapy enhancement.which was verified at the level of both mice colorectal cancer CT26 cell and tumor model.