超支化聚合物用于材料抗蛋白非特异性吸附的研究

When the biomaterials are contacted with biological fluids, such as blood or other body fluids, nonspecific protein adsorption is known to be the first event that occurs on the material surfaces. That will lead to a cascaded of host responses including blood coagulation, thrombus formation, platelet activation, cell and bacterial infection, and other undesirable responses. .The material which resists the nonspecific protein adsorption has attracted scientist's great interest in recent years.These materials interact with water strongly to prevent the nonspecific adsorption of protein molecules. Thus the sebsequent a series of biochemical reactions can be attenuated, reaching the purpose of preventing clotting and reducing the rejection and so on..In this project, the substrate surface will be modified by hydrophilic highly branched polymers to reduce nonspecific adsorption of the protein.Highly branched polymer has properties of excellent solubility and a large number of functional groups, that makes it possible to modify the surface of material according to actual needs for improving the material resistance to protein adsorption. It is expected to obtain the biomedical material with the excellent performance of resisting protein nonspecific adsorption. In addition, a large number of surface functional groups of the hyperbranched polymer can also be used for coupling antibodies. Because of low protein adsorption of substrate coupled with the hydrophilic highly branched polymer, the material can detect the specificity of a particular protein in the plasma. Given the background of the broad application of the biomedical polymer materials, this new type of resisting protein nonspecific adsorption of biomedical materials has important academic and practical application prospects.

当生物医学材料与血液接触时，血液中的蛋白质会非特异性吸附在材料表面，导致了血小板的黏附和血栓的形成。抗蛋白质非特异性吸附材料是近年来被广泛研究的新一代生物医学材料，它通过与水的强烈相互作用防止了蛋白质分子的非特异性吸附，从而避免了后续的一连串生化反应，达到防止凝血、降低排异等目的。本项目针对现有抗蛋白质非特异性吸附材料的局限性，提出利用亲水性高度支化聚合物修饰基体表面降低蛋白质的非特异性吸附。高度支化聚合物溶解性能优异，且表面具有大量官能团，可以根据实际需要进行表面改性提高材料抗蛋白吸附性能，有望得到性能优异的抗蛋白质非特异性吸附生物医学材料。高度支化聚合物的表面官能团还可用于耦合抗体，由于与基体偶联的亲水高度支化聚合物具有超低蛋白吸附背景，所以该材料还能实现血浆中特定蛋白的特异性检测。

当生物医学材料与血液接触时，血液中的蛋白质会非特异性吸附在材料表面，导致了血小板的黏附和血栓的形成。抗蛋白质非特异性吸附材料通过与水的强烈相互作用防止了蛋白质分子的非特异性吸附，从而避免了后续的一连串生化反应，达到防止凝血、降低排异等目的。本项目的研究通过调控超支化聚合物支化拓扑结构来优化抗蛋白吸附性能。设计合成了具有不同支化拓扑结构的超支化聚合物poly(VBPT-co-PEGMA) 。通过氨解反应，将超支化聚合物的末端基团转化成巯基，借助于Au-S键，将超支化聚合物接枝到金表面。通过原子力显微镜（AFM）及表面静态接触角（CA）测试，研究了超支化聚合物修饰后金表面的表观形貌及亲水性。通过荧光显微镜（FIM）和石英晶体微天平（QCM-D）对超支化聚合物修饰后金表面的抗蛋白吸附性能进行了研究。结果表明，经过超支化聚合物修饰后，金表面的蛋白吸附量明显降低，并可通过控制超支化聚合物的支化结构，对蛋白吸附性能进行优化，得到抗蛋白非特异性吸附性能优异的材料表面。在实际的生物应用中，金纳米棒比金基底更具有优势，因此改用金纳米棒作为待修饰材料。使用CTAB/SDBS双表面活性剂体系改良金种法，获得了高产率、长径比可调节的金纳米棒，并且该体系具有优良的抗碘杂质干扰的能力。用壳聚糖修饰后的金纳米棒其细胞毒性显著下降。