Preparation And Application Of Ultra-thin Two-dimensional Titanium Dioxide Nanosheets

With the development of human society and industry,more and more environmental pollution problems have arisen,and at the same time,the incidence of cancer has increased year by year.It is reported that about 1.5 million people die of lung cancer every year.Although modern medicine has made significant progress over the past decade,the survival rate of lung cancer patients remains low.There is currently no effective treatment for lung cancer,so new treatment strategies need to be explored to address these issues.At present,the biological application of nanosheets is rapidly increasing,providing new possibilities for improving the efficacy of cancer chemotherapy and radiotherapy.Here,a novel nano drug,doxorubicin?DOX?loaded titanium peroxide?TiOx?nanosheets,was designed and synthesized for the synergistic treatment of lung cancer.Using P123 as a soft template,ultra-thin two-dimensional?2D?TiO₂ nanosheets with large specific surface area were successfully prepared in a conventional solvothermal process.TiOx nanosheets were obtained by oxidizing TiO₂ nanosheets with H₂O₂ and then electrostatically adsorbed.The anticancer drug?DOX?is effectively supported on the surface of the TiOx nanosheet.In addition,under X-ray irradiation,the TiOx nanosheet promotes the production of reactive oxygen species including H₂O₂,·OH and·O₂^-,which is used for cancer radiotherapy.Drug release in cancer cells is effective,so that chemotherapy and radiotherapy are effectively combined for the synergistic treatment of cancer.The experimental results confirmed that TiOx/DOX nanomedicine can treat cancer under the dual stimulation of pH and X-ray irradiation.The cytotoxicity,cellular uptake and intracellular localization of the drug were evaluated in A549 cells.The results indicate that the TiOx/DOX complex exhibits greater cytotoxicity to A549 cells than free DOX.The therapeutic effects of DOX loaded TiOx nanosheets strongly depend on their loading mode and improve chemical and radiological efficacy under X-ray irradiation,which provides a major breakthrough in TiOx as a photoactive drug carrier in cancer chemotherapy and radiotherapy.Subsequently,TiO₂ nanosheets were applied to photocatalytic degradation of dyes.The effects of different calcination temperatures on the microstructure and photocatalytic properties of ultra-thin two-dimensional TiO₂ nanosheets were investigated.The ultra-thin structure can reduce the recombination of electron-hole pairs,and the calcination can introduce defects into the TiO₂ nanosheets to reduce the band gap of the two-dimensional material.The TiO₂ nanosheets obtained by calcination showed good degradation effects on Rhodamine B?RhB?and methylene blue?MB?under visible light irradiation,making them widely used in energy and environment.This excellent catalytic effect is mainly attributed to two points:on the one hand,the two-dimensional ultra-thin structure can reduce the path of photogenerated electrons and holes transported to the surface of the TiO₂ nanosheet,reduce the possibility of their recombination and increase the carrier lifetime,thereby improving the catalytic performance;on the other hand,the low structural stability of TiO₂ nanosheets is introduced,defects are introduced,and the absorption efficiency and utilization of visible light are improved,thereby improving the visible light catalytic performance.