【作者】 李国柱；

【导师】 张凤宝；

【作者基本信息】 天津大学 ， 化学工程， 2010， 博士

【摘要】 有效抵抗生物分子和微生物在表面的非特异性吸附是诸多领域(例如生物仪器和船舶等)的巨大挑战。例如蛋白的非特异性吸附既会降低基于表面的诊断仪器的性能又会在植入的生物材料的愈合过程中引起不良反应。本文使用一系列两性离子聚合物和黏性儿茶酚基团进行表面改性以制备超低污染表面,并对其应用进行了研究。实验中使用SPR传感器对表面蛋白吸附进行测量,使用层流流动室原位观察表面细菌粘附/生物膜形成情况。本文首先研究了将含有黏性儿茶酚基团的引发剂粘接到表面后引发聚合磺酸甜菜碱聚合物(“graft from”方法),从而制备出了超低污染表面。改性后的表面可以高度抵抗单一蛋白溶液和人体血浆、血清的非特异性吸附,并且在PBS中浸泡42天后依然保持其抗污染性能。进而,实验对假单胞菌在改性的氨基玻璃片表面的生长、聚集状况进行了原位观测研究,时间为9天。实验结果表明使用这种方法连接的两性离子聚合物涂层可以显著减少假单胞菌的粘附和生物膜的形成,从而证明了儿茶酚基团粘接两性离子聚合物的高效性和稳定性。基于上述“graft from”表面改性研究,本文进而研发了带有一个儿茶酚基团的磺酸甜菜碱聚合物。实验考察了该黏性聚合物在不同表面化学和酸碱条件下的粘接效果。在优化条件之下,改性后的表面可以有效抵抗来自单一蛋白溶液和人体血液、血清的非特异性吸附。同时,对假单胞菌在改性表面上生长、聚集进行了为期3天的评价。实验结果表明,改性表面可以有效抵抗细菌粘附和生物膜的形成。本章研发的黏性磺酸甜菜碱聚合物可以进行简便、高效的表面改性从而获得超低污染表面,并可以应用于复杂体系。进而,设计、合成了两种不同类型的带有两个儿茶酚基团的引发剂。然后通过这两种引发剂和离子对单体的聚合得到的两种电性均衡的黏性聚电解质:其中一种聚电解质由ATRP得到、分子中带有两个儿茶酚粘接基团和两个抗污染聚合物臂;另一种则由简单的自由基聚合制得。实验研究表明两种聚电解质不但可以有效地粘接到金表面而且在表面上可以实现电性均衡。进而,测量了改性后的表面对纤维蛋白原、溶菌酶和牛血清白蛋白溶液的非特异性吸附。结果表明,两种黏性聚电解质改性后的表面都具有很好的抗污染性能。同时研究中使用离子对制备黏性聚电解质的策略不需要调节带电单体的比例即可使其电性均衡。为了快速、高效地制备可功能化的超低污染表面,本文进而研发了一种可功能化的黏性两性离子聚合物(pCB2-catechol2)。该聚合物由具有双臂双功能(超低污染和可功能化)的羧酸甜菜碱聚合物部分和具有表面粘接功能的双儿茶酚部分组成。实验考察了该黏性聚合物在各种条件下(pH值和溶剂)在金表面的粘接效果。在优化条件下,pCB2-catechol2的表面改性结果同其他两种聚合物(即pCB-catechol和pCB-catechol2)进行了比较。结果表明pCB2-catechol2在制备超低污染表面上具有明显的优势。进而,将抗活化白细胞黏附分子(anti-ALCAM)直接固定在pCB2-catechol2改性后的表面上。结果显示固定抗体后的表面保持了其超低污染性能。同时固定的抗体也显示了很好的生物活性,该表面可以对100%人体血浆中的活化白细胞黏附分子(ALCAM)进行高灵敏度和高特异性的的检测。这一工作阐述了一种制备可功能化和超低污染表面的简便和有效的方法,且该方法将来极有希望用于医学检测中。更多还原

【Abstract】 A great challenge in many applications, ranging from biomedical devices to ship hulls, is the prevention of nonspecific biomolecular and microorganism attachment on surfaces. For example, nonspecific protein adsorption degrades the performance of surface-based diagnostic devices and causes an adverse effect on the healing process for implanted biomaterials. Herein ultralow-fouling zwitterionic surfaces were prepared via adhesive mussel mimetic linkages. Protein adsorption was measured using a surface plasmon resonance (SPR) sensor, and the accumulation of Pseudomonas aeruginosa on the surfaces was studied in situ using a laminar flow chamber.Nonfouling sulfobetaine polymers were first grafted via surface-initiated atom transfer radical polymerization (ATRP) from surfaces covered with an adhesive catechol initiator. The nonfouling performances of the resulting polymer brushes on gold and NH2-gold surfaces were compared. Under optimal conditions, ultralow protein adsorption from both single protein solutions and blood plasma/serum was achieved. Furthermore, the 9-day accumulation of Pseudomonas aeruginosa on the treated glass surfaces was studied. The results showed that these sulfobetaine coatings dramatically reduced the biofilm formation of P. aeruginosa as compared to the reference bare glass.Biomimetic polymers with a poly(sulfobetaine) (pSB) moiety for ultralow fouling and a catechol end group for surface anchoring have been developed. Binding tests of the adhesive polymer on various surfaces, including amino (NH2), hydroxyl (OH), and methyl (CH3) terminated self-assembled monolayers (SAMs) along with bare gold, were performed under acidic and basic conditions. Under optimized conditions, the coated surfaces are highly resistant to non-specific protein adsorption from both single protein solutions and blood serum/plasma. Furthermore, the 3-day accumulation of Pseudomonas aeruginosa on the coated surfaces was evaluated. Results show that the coated surfaces are highly resistant to biofilm formation. This work demonstrates a convenient and efficient method for using zwitterionic polymers to achieve ultralow fouling surfaces via surface modification, for applications in complex media.Furthermore, two kinds of nonfouling polyampholytes with biomimetic adhesive groups were synthesized by the polymerization of a cationic-anionic comonomer using two types of catecholic initiators. One polyampholyte with two catechol anchoring groups and two nonfouling zwitterionic arms was obtained by ATRP, and the other one was got by free radical polymerization. Results showed that the surfaces modified with both of these polymers had excellent nonfouling properties.Finally, a biomimetic polymer (pCB2-catechol2), with two zwitterionic poly(carboxybetaine) (pCB) arms for ultralow fouling and two adhesive catechol groups for surface anchoring, was developed. Binding tests of pCB2-catechol2 were performed on a gold surface under a range of conditions (various pH values and solvents). Protein adsorption from single protein solutions blood plasma/serum was evaluated. Results were compared with those from two other polymers (i.e., pCB-catechol and pCB-catechol2). Furthermore, the direct immobilization of anti-activated leukocyte cell adhesion molecule (anti-ALCAM) was carried out on the pCB2-catechol2 modified surface. Results showed that the antibody-immobilized surface maintained its excellent ultralow fouling properties. The detection of activated leukocyte cell adhesion molecule (ALCAM) in 100% blood plasma with high sensitivity and specificity was achieved. This work demonstrates an effective and convenient strategy to obtain functionalizable and ultralow fouling surfaces.更多还原