基于上转换荧光成像协同FLIM监控的纳米光动力精准靶向治疗研究

To face the difficulty that how to achieve precise photodynamic therapy (PDT) of cancer cells, the project will be located on constructing upconversion nanomaterials which convert the near-infrared light within optical biological window for upconversion imaging (UCIM), and associating with the fluorescence lifetime imaging microscopy (FLIM) technology of photosensitizer, to build a dynamicly monitored, precisely targeted and precisely treating photodynamic therapy platform. On one hand, the key research is to build efficient near-infrared light excited, targeted upconversion nano-photodynamic therapy platform, which utilize the stable UCIM with low autofluorescence, and FLIM to technically monitoring the targeted process of cancer cells. Then the targeting ability of nanoparticle for cancer cells will be precisely assessments and modified for more efficiently targeting. On the other hand, combing the UCIM and exquisite FLIM technology, dynamicly monitor the process of nano-drugs killing cancer cells. The results about the relating parameters about PDT and related cellular microenvironment information will help to achieve precisely assessment of the relevant treatment method, to establish more precise and efficient photodynamic therapy. This project examines the implementation of these important issues, accurate diagnosis and treatment for cancer research, which provides a foundation for presice therapy of cancers with important scientific significance and application prospects.

针对实现癌症精准光动力学治疗（PDT）的关键科学问题 , 本项目将位于生物光学窗口内的近红外光上转换纳米材料的上转换荧光成像（UCIM）与光敏剂的荧光寿命显微成像(FLIM)技术相结合, 以期研究构筑可监控的、精准靶向的、精准治疗的光动力治疗平台。重点研究：通过构筑高效近红外光激发的、具有表面靶向配体的纳米上转换光动力治疗材料，利用不激发生物体自体自荧光、发光稳定的上转换荧光纳米探针及FLIM技术监测纳米粒子的靶向过程及治疗过程, 对纳米粒子表面配体的靶向能力进行相关评估；利用UCIM和FLIM复合成像技术，动态监测低光损伤、穿透深度深的上转换纳米药物对癌细胞的杀伤过程及相关细胞微环境参数，实现对相关治疗参数的精准评估。开展上述重要问题的研究，将为癌症的精准的诊疗研究提供新的方法和手段，并提供了研究基础和科学依据，具有重要的科学意义和应用前景。

针对实现癌症精准光动力学治疗（PDT）的关键科学问题，1）完成了高效的染料ICG敏化单掺杂Er3+离子的上转换和下转换发光，证明了连接ICG分子后，由于ICG和Er3+之间能量传递降低了ICG的光漂白，增强了光热效应，同时实现了近红外二区发光增强和深组织穿透深度的生物成像。2）在增强808nm激发的上转换发光方面，确立染料敏化的上转换过程清晰的物理图像，包含能量转移（ET),反向能量转移（EBT）和能量迁移（EM)。尤其是，超强吸收的染料分子和大数量的染料分子连接到上转换纳米粒子的表面，不仅增强了能量转移敏化增强上转换发光，同时也产生了不利的上转换纳米粒子到染料分子的反向能量转移。3）通过染料敏化上转换纳米粒子实现了在不损失上转换发光（UCL）强度的条件下（上转换的发光甚至增强几十倍），调控了R/G发射比。调控的R/G发射比基本上源于调控Er3+的红光和绿光的布局过程。我们证明了可以通过连接不同数目的染料分子精确的调控R/G发射比。4）通过类三明治结构实现808nm激发的Nd3+敏化体系的上转换发光及下转换发光。通过引入惰性核和惰性壳可以显著的提高Nd3+敏化的上转换发光强度。增加惰性核的尺寸，压缩了发光中心壳层和Nd3+敏化的壳层，显著的增强上转换的发光。通过引入NaYF4惰性核，掺杂的发光中心离子被限制在二维平面，增加Yb3+和发光中心之间的能量传递速率。5）建立荧光寿命成像技术实时监测光动力治疗光敏剂的荧光寿命（FLIM）的新方法，获得了实时监控上转换纳米光敏剂光动力的新技术。.本项目发表学术4篇SCI论文，申请专利2项。