高灵敏成像检测慢性炎症介导的癌变细胞及活体内活性氧自由基变化的功能纳米荧光探针研究

Chronic inflammation induced by biological, chemical, and physical factors is closely associated with increased risk of human cancer.Recent data show reactive oxygen species (ROS) play a key role in inflammation-mediated carcinogenesis.However, in this pathway, cellular and molecular mechanism remains unclear.Nowdays, it is hot spot how to devolope fluorescence imaging methods for detection of ROS in chemical and medical science. Because ROS are short life and extreme low concentration during cancinogenesis, existing fluorescent probes can not detect sensitively these biological reactice small molecules inside live cells and in vivo. To solve above-mentioned problems, we plan to construct functional fluorescent nanoprobes based on covalent and noncovalent synergetic assembly, via surface modification of novel upconversion nanoparticles using ROS-responsive units, or assembly of amphiphilic polymers modified with ROS-responsive groups. Functional fluorescent nanoprobes prepared are able to visualize true ROS levels and small fluctuations in cells and subcellular regions,based on fluorescent signal amplification mechnism resulted from energy transfer mediated by specific and rapid reaction with ROS. Thus, exact information of molecular events that ROS are involved in can be reliably reported during carcinogenesis caused by chronic inflammation.

由于生物、化学及物理因素导致的慢性炎症与癌症风险的提高密切相关，研究表明活性氧自由基在炎症介导的细胞癌变过程中发挥关键作用，但其细胞与分子机制尚未得到明确结论。发展高灵敏度的荧光成像方法检测体内活性氧的变化是目前化学及医学领域研究的热点及难点问题。而活性氧的寿命短，癌变过程中活性氧的实际浓度极低，目前的荧光探针还无法对其真实浓度及其微小波动作出响应。针对以上问题，本项目通过在新型上转换纳米颗粒表面修饰与单一活性氧特异性响应的分子识别单元，或利用修饰有活性氧响应单元的两亲性聚合物，协同组装得到功能纳米探针。利用探针与活性氧的高选择性、快速反应过程实现能量传递,触发荧光信号放大机制，极大地提高检测灵敏度，从而在细胞、亚细胞水平上，实现对低水平活性氧的高灵敏度可视化示踪，获得慢性炎症介导细胞癌变过程中，细胞及活体内活性氧自由基参与分子事件的真实信息。

慢性炎症与癌症的发生密切相关，研究表明活性氧自由基在炎症介导的细胞癌变过程中发挥关键作用，但其分子机制尚未得到明确结论。究其原因是活性氧的寿命短，癌变过程中活性氧的实际浓度极低，目前的荧光探针还无法对其真实浓度及其微小波动作出响应。针对以上问题，本项目构建了一系列新型荧光探针，建立了细胞及活体水平的成像方法，获取了活性氧及相关生物分子调控炎症与癌症发生发展的重要信息。主要研究内容包括：1) 基于瞬时、可逆的特异性识别反应，建立了实时、动态 、原位成像活性分子的新方法; 2) 利用超高灵敏度探针，解决了生物体内极低真实浓度活性分子检测的难题; 3) 利用准确靶向细胞器探针，揭示了细胞凋亡等事件中活性分子的亚细胞分布 ; 4)利用光谱时空可分辨多色探针，解决了活性分子多组分同时检测的难题。本项目为在细胞、亚细胞水平上研究慢性炎症介导细胞癌变过程中，细胞及活体内活性氧自由基的调控作用提供了新的成像材料与技术。