Preparation Of Anatase TiO₂-based Nanostructure Films And Their Light-induced Cell Deachment Performance

Cell sheet technology, making up for the shortage of traditional tissue engineering, has become an important area in the research of tissue engineering due to its scaffolds-free advantage. It can transplant monolayer or multilayer cell sheets to the host and repair the injured tissue. Therefore, how to harvest a large amount of cell sheets effectively becomes the key issue of this technology. TiO2 nano films have been widely applied in biomedical filed due to their excellent biocompatibility, also,it is found to have the ability of light-induced cell sheet detachment. In this dissertation, based on our previous work on light-induced cell detachment from anatase TiO2 nanodots films, different pretreatment methods are adopted to optimize the way of sterilization so that the efficiency of detachment could be improved. Moreover, TiO2 films with different nanostructures, including nanodots film, dense film and porous film, are investigated for their influences on light-induced cell detachment. The main researches focused on morphology, crystalline, chemical composition, surface wettability and cell compatibility of the films. Based on these results, films were applied to light-induced cell detachment. The activity and mechanism of pretreatment and film structure on cell detachment were explored. The main contents and conclusions are as followings:(1) Effects of different pretreatment methods on TiO2 nanodots and the optimization of detachment efficiency.First, TiO2 nanodots films were prepared through self-assembly method. Then four different pretreatment methods, including UV254, UV254-AC, UV254, AC-UV254, are adopted on TiO2 nanodots. All the films showed excellent cell compatibility, among them, UV254 and UV254-AC treated films showed better cell adhesion. For cell detachment, all the films show excellent light-induced cell detachment, after 20min illumination, over 85% cells were detached from the films. Again, UV254 and UV254-AC treated films showed improved performances, they reached 85% and 87% detachment, respectively, after only 15min illumination.(2) Effects of film nanostructure on cell detachmentFirst, TiO2 nanodots film, dense film and porous film were prepared through self-assembly method with different additives in the precursor solution. All the films showed the excellent cell compatibility, while nanodots film and porous film showed better cell adhesion and proliferation. All three films showed the excellent light-induced cell detachment, after 20min illumination, over 85% cells were detached from the dense films. Nevertheless, for nanodots film and porous film, it takes only less than 15min illumination to reach 90% and 85% detachment, respectively.