基于多共价键原理构筑稳定的两性离子聚合物刷及其在人工组织表面摩擦学中的应用研究

Polymer brushes consist of macromolecules that are constrained with one end at a surface or interface with a sufficiently high density to form a special polymer conformation. The physicochemical properties of the surface can be controlled by tethering polymer brushes, which has numerous applications, such as molecular switches, anti-protein adsorption and controlled release. However, most of the polymer brushes have the problem of instability in application, which severely limits their broad applications and developments in many fields. In this project, the principle of multivalency will be proposed to fabricate stable brushes in water. First, the research will proceed from the synthetic method to explore the exact bond broken position between the polymer brushes and surfaces by replacing the siloxane with other chemical bonds. In term of the results, the design and synthesis of stable polymer brushes can be achieved. Meanwhile, the concept of multivalent can be introduced to fabricate novel brushes. By optimizing the synthetic methods and steps, the stability of polymer brushes can be substantially enhanced in water. Finally the stable polymer brushes can be applied in artificial lubricants and surface modification of human joint prosthesis and catheter. Then the tribological properties and durability will be evaluated. The implementation of the research will provide new ideas and methods for the design and synthesis of stable polymer brushes in water phase. Meanwhile, 1-2 series of methods can be exploited to fabricate stable polymer brushes for potentially clinical application, which will broaden the application and development of polymer brushes in biomedical materials.

聚合物刷是指聚合物分子链一端以相对密集的方式接枝在基底或界面上形成的一种特殊高分子结构。通过接枝聚合物刷调控材料表面的化学与物理性能在许多领域都有着重要的应用，如分子开关、抗菌及药物控释等。然而大多数聚合物刷在应用中都存在着稳定性差的问题，这严重限制了其更广泛的发展前景。本项目拟引用多共价键的概念来制备在水相中稳定的聚合物刷：首先从合成方法入手，通过用不同的连接键替换硅氧烷键来探究聚合物刷在水相中的具体断裂位置，为设计稳定的聚合物刷提供依据；然后利用多共价键的原理制备新型的聚合物刷，优化合成路线及步骤，提高其在水相中的稳定性；最后将稳定的聚合物刷应用到人工组织润滑液，人工关节和导尿管的表面，并对接枝后的摩擦性能及使用寿命进行测试评估。本项目的成功实施，将为制备水相中稳定的聚合物刷提供新的思路和研究方法，同时有望开发出1-2类具有临床应用前景的稳定聚合物刷，推动其在生物医学材料方面的发展。

随着科技的发展医疗水平在逐渐的进步，由细菌引起的感染依然是医疗卫生领域日益严重的问题之一。特别是在临床植入手术时，一旦发生细菌感染，就会造成手术失败。植入体表面抗菌涂层的修饰可以有效地抵挡细菌的侵入，例如使用共价键修饰的聚合物刷。然后聚合物刷在水溶液中容易脱落，从而降低涂层的功能性。在本报告中，我们致力于利用多共价键制备稳定的聚合物刷涂层用于植入体的表面修饰。不仅可以得到在水相及生理环境下稳定的聚合物刷，还具有较好的生物安全性。体内、体外实验均验证了该方法制备的聚合物刷涂层可以有效地抵抗细菌的感染与粘附。该涂层在临床医疗中规避植入体感染方面具有重大的价值和潜力。另外，我们还制备了一种多功能伤口敷料，其海绵状结构为材料提供了良好的血液和组织渗出液吸收能力。体外和体内实验均表明，该冷冻凝胶显示出优异的光热响应性，并能促进细胞增殖和皮肤再生。因此，该冷冻凝胶可做为具有止血，抗菌，促细胞增殖的多功能伤口敷料，在临床伤口愈合方面具有巨大的应用潜力。