本项目拟以稀土掺杂的上转换纳米晶、超薄MoS2纳米片以及生物可降解的MnO2为结构基元，构建一种pH响应的上转换荧光成像精确引导的光热治疗体系，即中空UCNPs@MoS2@MnO2。该材料在中性环境中稳定存在，980nm激发光辐射下，UCNPs的上转换荧光完全被MoS2吸收；而在酸性环境中，MnO2层分解，释放出单独的UCNPs和MoS2，因而在980nm激发光辐射下可以检测到上转换荧光。此外，MoS2纳米片对980nm激发光有较强的吸收，因此在980nm激发光下中空UCNPs@MoS2@MnO2具有较高的光热转换效率。本项目拟建立小鼠肿瘤模型，分别以尾静脉注射和原位给药的方式进行肿瘤部位pH响应的上转换荧光成像精确引导的光热治疗研究。该课题可为建立pH响应快、检测灵敏度高且光热治疗效果好的肿瘤诊疗体系奠定坚实的理论基础和实验依据，有利于推动集肿瘤诊断和治疗于一体的生物探针体系的研究进程。

This project intends to construct a photothermal treatment system precisely guided by pH response upconversion luminescence imaging, which is based on rare earth ions doped upconversion luminescence nanocrystals, ultra-thin MoS2 nanosheets and biodegradable MnO2 nanocrystals, i.e. hollow UCNPs@MoS2@MnO2. The composite nanomaterials can exist stably in neutral environment, under 980 nm excitation, the upconversion luminescence of UCNPs can be completely absorbed by MoS2 nanosheets. In acidic environment, MnO2 is decomposed and composite structure is disintegrated, resulting in the release of individual UCNPs nanocrystals and MoS2 nanosheets. Therefore, upconversion luminescence can be detected under 980 nm excitation. In addition, MoS2 nanosheets have strong absorption of 980 nm excitation light, so hollow UCNPs@MoS2@MnO2 has high photothermal conversion efficiency under 980 nm excitation. This project intends to establish the mouse tumor model, which can be used to study the photothermal therapy of the tumor site under the precise guidance of the pH responsed upconversion luminescence imaging via tail vein injection and in situ administration, respectively. This project can lay a solid theoretical foundation and experimental basis for the establishment of a tumor diagnosis and treatment system with fast pH response, high detection sensitivity and good photothermal treatment effect, and is conducive to promoting the research process of the biological probe system which integrates the diagnosis and treatment of tumors.