光声成像技术是目前生物医学领域新兴的一种非辐射、无损伤检测技术，被迅速用于肿瘤成像研究。其中，具有近红外吸收的光声探针在肿瘤靶向成像方面日趋受到关注，开发具有光稳定性好、近红外吸收强、靶向性高以及生物相容性好的光声探针正成为研究热点。针对上述要求，本课题提出开发基于水溶性共轭高分子的新型光声探针，即充分利用其本身光吸收强、光稳定性好以及生物毒性小的特点，通过在具有强近红外吸收共轭高分子的侧链引入聚乙二醇链，进一步提高其水溶性和生物相容性；从调控分子的组成、大小和功能基团等，研究高分子在不同环境下分子构型、聚集态和光声信号的变化及相关的构效关系；修饰对肿瘤细胞表面高表达的整合素αvβ3具有靶向作用的RGD肽，研究高分子与其高效偶联及标定方法；通过研究RGD靶向高分子光声探针对肿瘤细胞的靶向性以及针对裸鼠动物模型的肿瘤靶向成像，对高分子光声探针的效能进行评价，为高性能光声探针的发展做出贡献。

Photoacoustic imaging now is a new technique with no radiation, no damage properties in biomedical field and is rapidly being used for tumor imaging. Among them, photoacoustic probes with near infrared (NIR) absorption in the targeted tumor imaging is becoming more and more attention. Developing probes with good optical stability, strong NIR absorption, good targeting and biocompatibility are becoming a hot spot. According to the above requirements, our project proposed to develop novel photoacoustic probes based on water soluble conjugated polymer with native strong light absorption, light stability and biocompatibility. Firstly, the water-solubility and biocompatibility of conjugated polymer with strong NIR absorption are enhanced through introducing polyethylene alcohol to their side chains. Secondly, the structure-optical property relationships are investigated via adjusting the molecular composition, size, aggregation, and their functional groups under different environment. Thirdly, the crosslinking and quantity analysis were studied on conjugated polymers modified with RGD peptides which can target integrin α V β 3, the highly expressed molecules on the tumor cell surface. Finally, the performances of the probes are evaluated through investigating the RGD targeting property to tumor cells and the tumor imaging in vivo. We hope this work will be beneficial to developing photoacoustic probes with high performances.