基于能量迁移机理的下转移近红外荧光纳米温敏材料的研究

Luminescent nanothermometry has proved to be an excellent noninvasive alternative in terms of its advantages of remote observation, high sensitivity, good spatial resolution and short response time. However, the well-researched luminescent nanothermometers based on fluorescence intensity ratio technique exhibit low signal discriminability and temperature sensing sensitivity on account of the limitation of their intrinsic temperature sensing mechanism, which still lags behind people’s demand for temperature sensing in actual biomedical applications. Hence, it is of great significance to develop new luminescent nanothermometers with novel thermo-sensitive mechanism, which would promote the development of luminescent nanothermometry and expand their application fields. In this project, we designed a core@multi-shell nanostructure with a high-efficiency temperature-sensitive energy migration channel based on the high sensitivity of energy migration efficiency to work distance. By changing the thickness of the intermediate transition shell and the doping concentration of Yb3+ ions, the energy migration efficiency and the temperature dependent fluorescence intensity ratio of active ions can be effectively controlled. The relationship between the nanostructure design (transition shell thickness and Yb3+ doping concentration), energy migration efficiency and temperature dependent fluorescence intensity ratio of active ions will be defined, a new temperature sensing mechanism based on thermo-sensitive down-shifting energy migration near-infrared fluorescence process and the down-shifting near-infrared fluorescent nanostructure materials with the best temperature sensitivity will be developed. This project will lay a theoretical and experimental foundation for the development of new high performance fluorescent nano-sensors based on novel temperature sensing mechanism.

荧光纳米测温技术具有可远程监测、高灵敏度、高空间分辨率、快速响应等优点，成为最具有应用潜力的非接触式光学测温技术。迄今广泛研究的基于荧光强度比型纳米测温技术由于自身测温机理的限制，在测温范围和测温灵敏度上仍有较大的提升空间。因此，开发新颖荧光温敏机制的温敏材料有利于拓展荧光纳米温敏材料的应用领域，促进荧光纳米测温技术的发展。本项目基于稀土离子间的能量迁移效率对作用距离的敏感性出发，设计具有高效温敏下转移能量迁移通道的核@多壳层纳米结构。通过改变中间过渡壳层的厚度及Yb3+离子的掺杂浓度，有效调控下转移能量迁移的效率及荧光强度比的温度依赖特性，明确纳米结构设计-下转移能量迁移效率-荧光强度比温度依赖性的关系，发展基于能量迁移机理的下转移近红外荧光测温新机制，寻找最佳温敏性能的下转移近红外荧光纳米结构材料，为开发基于新颖温敏机制的新型高性能荧光纳米温度传感器奠定理论和实验基础。

稀土掺杂的荧光纳米测温技术提供了高灵敏度、高空间分辨率、远程可视化监测的温度传感模式，对于微电子电路、微流控设备的“热点”监控，以及纳米生物医学的精确诊疗具有重要应用前景。然而，稀土荧光纳米测温技术实现高荧光效率的“近红外二区至三区光学窗口”发射，并以此光学窗口构建高灵敏度的温度传感，仍然充满了挑战。本项目基于稀土离子间的能量迁移效率对作用距离的敏感性出发，设计了具有高效温敏下转移能量迁移通道的核@多壳层纳米结构。通过改变中间过渡壳层的厚度及Yb3+离子的掺杂浓度，有效调控下转移能量迁移的效率及荧光强度比的温度依赖特性，明确纳米结构设计-下转移能量迁移效率-荧光强度比温度依赖性的关系，发展基于能量迁移机理的下转移近红外荧光测温新机制，寻找最佳温敏性能的下转移近红外荧光纳米结构材料，为开发基于新颖温敏机制的新型高性能荧光纳米温度传感器奠定理论和实验基础。