骨关节炎(Osteoarthritis,OA)是一种常见多发病。糖胺聚糖（GAGs）的减少被认为是骨关节炎软骨退变早期的标志性事件。在软骨退变阶段进行针对于GAGs靶向的早期分子成像，可以帮助医师及早诊断骨关节炎并进行治疗,使患病关节的病情得到明显改善。在我们的前期工作中，发现DPA-Zn能和关节软骨中的GAGs靶向结合，并将其应用在骨关节炎软骨退变的早期光学分子成像研究中。但由于探针的水溶性差和光学成像的较低空间分辨率、低成像深度，限制了其进一步转化应用。本课题拟研究新的软骨退变GAGs靶向水溶性黑色素纳米光声分子探针，来进行骨关节炎的早期分子诊断。本项目通过水溶性基团氨基聚乙二醇叔丁醇酯（PEG）将DPA-Zn分子连接到水溶性黑色素纳米粒子表面，获得富含正电荷的纳米分子探针，选择性识别GAGs，进行针对于骨关节炎软骨退变的早期分子光声成像，为其在骨关节炎早期分子诊断的应用奠定基础。

Osteoarthritis (Osteoarthritis, OA) is a common bone and joint disease. The incidence rate of OA is around 50% in people over 50 years old. Clinical studies show that, the joint condition can be improved obviously if the arthritis is early detected and treated promptly. In OA, glycosaminoglycans (GAGs) reduction is considered to be the symbol of the early stage of cartilage degeneration. This research attempts to develop a new GAGs targeted water-soluble MNP-PEG-DPA-Zn photoacoustic imaging nano-probe, to early detect osteoarthritis molecularly. In our previous work, we found DPA-Zn could bind to GAGs in articular cartilage, and applied it in optical molecular imaging of OA early detection. But because the probe’s poor water solubility, as well as the low resolution and depth of optical imaging, limits its further biological application. The project is to design and develop a water soluble positive charged MNP-PEG-DPA-Zn, to target GAGs, and for the early detection of cartilage molecular photoacoustic imaging, and lays foundation for its application in OA molecular imaging.