激活型比率荧光纳米诊疗探针的构建及活体应用研究

Developing the activatable photosensitizer with spatiotemporal control of singlet oxygen release is of great significance to achieve selective imaging and on-demand photodynamic therapy (PDT) of tumors. At present, the activatable photosensitizer based on single-wavelength fluorescence emission in tumors suffers from the limits of imprecise localization, low-sensitivity in imaging, poor PDT efficiency and so on. In this project, we intend to use the strategy of ratiometric fluorescence imaging to develop a tumor targeted and tumor related factor stimuli-activatable ratiometric fluorescence theranostic nanoprobe, which realizes the integrative research concerning accurate localization, sensitive imaging and imaging-guided high efficient PDT of tumors in vivo. The investigations in this project mainly include: (1) designing appropriate fluorescence molecules and organic photosensitizers to construct a novel multi-channel fluorescence emission nanophotosensitizer, which is on the basis of the dual fluorescence resonance energy transfer mechanism to enable remarkable singlet oxygen production; (2) exploring the ratiometric fluorescence mechanism between multi-channel fluorescence signal molecules and the specific response of tumor related factor, and building the method that integrates the tumor related factor activatable ratiometric fluorescence imaging and PDT; (3) investigating the efficacy of the tumor related factor activatable ratiometric fluorescence probe for diagnosis and PDT of tumors, which uses the nude mouse model with tumors as the research object. This project is expected to provide a new avenue for preparation of novel intelligent photosensitizers and present a new paradigm for highly efficient diagnosis and PDT of tumors.

发展单线态氧可控释放的激活型光敏剂，对实现肿瘤选择性成像和可控光动力治疗（PDT）具有重要意义。目前单一波长荧光发射的激活型光敏剂存在肿瘤精准定位困难、成像灵敏度低、PDT疗效不佳等问题。本项目拟融合比率荧光成像策略，开发恶性肿瘤主动靶向识别的、肿瘤相关因子激活的比率荧光纳米诊疗探针，实现对体内肿瘤的精准定位、灵敏成像和高效PDT一体化研究。主要包括:（1）基于二次荧光共振能量转移机制，设计合适荧光分子和有机光敏剂，构建高单线态氧量子产率的、多通道发射的新型纳米光敏剂；（2）探索多通道荧光信号分子与肿瘤相关因子特异性响应的比率荧光变化机制，建立肿瘤相关因子激活的比率荧光成像与PDT一体化的方法；（3）以相关肿瘤的裸鼠模型为研究对象，评估肿瘤相关因子激活的比率荧光探针诊断和PDT“切除”肿瘤的效能。本项目将为新型智能光敏剂的设计及高效的肿瘤诊疗一体化研究提供新的思路。

本项目中申请人利用纳米沉降技术，以两亲性脂质体为载体，构建了双波长发射的高1O2量子产率的新型纳米光敏剂。通过纳米组装和分子识别技术，成功构建了肿瘤细胞靶向识别，细胞内源性miRNA触发激活的双发射荧光纳米诊疗探针，实现活体水平肿瘤双波长荧光成像和成像指导的光动力（PDT）切除一体化研究。此外，基于这种纳米组装和分子识别技术，我们还成功的发展了肿瘤细胞内源性组织蛋白酶B和复杂生物、环境介质中有害物质的比率荧光传感新策略。在项目执行期内，先后Nano Today, Analytical Chemistry, Chemical Communications, Sensors and Actuators B: Chemical, ACS Applied Materials & Interfaces等期刊发表学术论文9篇（均标注本项目号）。这些研究工作对我们今后进一步发展高效比率传感策略用于活体层面疾病标志物的成像诊断和光动力学治疗一体化研究具有一定的指导意义。