环状构象PEG改性表面及其优越的抗凝血性能

Modified surface by poly(ethylene glycol) with looped conformation and its superior anticoagulant property

聚乙二醇(PEG)因其优异的抗蛋白质吸附能力成为抗凝血材料的首选.目前,多数研究都集中在PEG链长和接枝密度对蛋白质吸附的影响,鲜有关注PEG链构象影响的研究.本文利用硫金键在石英晶体微天平金片表面构建了两种不同分子量(MW=1000和MW=5000)的环状(SH-PEG-SH)和线型(m PEG-SH)构象的PEG改性表面,并研究了其抗纤维蛋白原吸附机理和抗凝血性能.X射线光电子能谱仪和原子力显微镜确定了不同表面的组成及其相结构.结果发现,环状构象的PEG表面相对于线型PEG构象能更加有效地抑制纤维蛋白原的吸附,同时具有更加优异的抗血小板和红细胞黏附性能.分析其蛋白质吸附机理发现,当PEG分子量较低时(MW=1000),其环状构象PEG表面抗纤维蛋白原吸附机理源于较高的表面覆盖率;当PEG分子量较高时(MW=5000),其抗纤维蛋白原吸附机理源于高黏弹性和高表面覆盖率共同作用的结果.本工作为构建抗凝血涂层提供了新的思路,并为制备高性能生物医用材料提供了理论基础.

Poly（ethylene glycol） （PEG） is currently the gold standard for anticoagulant coatings. Up to now, most researchers focused on the impact of chain length and grafting density of PEG on protein adsorption, but few concerned about the effect of PEG conformation. Gold surfaces of quartz crystal microbalance with dissipation （QCM-D） with looped （SH-PEG-SH） and linear （SH-PEG） PEGs with different molecular weights （Mw=1000 and Mw=5000） are prepared. Subsequently, fibrinogen adsorption and anticoagulant properties are measured as well. The compositions and phase structures of PEG modified surfaces are characterized by XPS and AFM. Compared with linear PEG surface, we find that looped PEG surface more efficiently prohibits fibrinogen adsorption, and then has superior antiplatelet and anti-erythrocytes adhesions properties. Fibrinogen adsorption results suggest that when the molecular weight of PEG is low （Mw=1000）, the main reason for the fibrinogen resistance of looped PEG is the large surface coverage; when the molecular weight of PEG is high （Mw=5000）, the fibrinogen resistance mechanism of looped PEG is a combination of the high viscoelasticity and the large surface coverage. This article provides valuable evidence and guidance for anticoagulant coating and application of high-performance biomaterials.