| 摘要: | 超親水雙離子材料具有和聚乙二醇(polyethylene glycol, PEG)相同的抗生物汙染(anti-biofouling)特性，因此被應用於生醫材料的表面修飾。在這研究中，我們提出一種建構抗非特異性吸附表面的新方法，以Michael addition方式，將雙離子材料接枝於聚多巴胺表面，使其具有1. 超親水性；2. 抵抗生物吸附；3. 可用於多樣基材表面修飾；4. 製備簡單與5. 多功能性。多巴胺因同時具有鄰苯二酚和胺基被證實能黏附於各種基材表面，形成聚多巴胺層，此化學結構中，俱有一級胺與二級胺官能基，可與甲基丙烯酸磺基甜菜鹼(Sulfobetaine methacrylate, SBMA)和丙烯醯胺磺基甜菜鹼(Sulfobetaine acrylamide, SBAA)雙離子單體藉由Michael addition接枝於表面，達到良好的抗生物汙染特性。
因此這項研究要先形成帶有大量的活性胺基官能基的聚多巴胺表面，並且藉由Michael addition反應使胺基和帶有乙烯基單體進行1，4加成，而將單體接枝於聚多巴胺表面，並應用於各種基板修飾。這裡我們比較三種抗吸附單體分別為SBAA、SBMA和聚乙二醇單甲醚甲基丙烯酸酯(poly(ethylene glycol) methacrylate, PEGMA)，並接枝於聚多巴胺表面使其達抗生物汙染之特性。利用水接觸角和X射線光電子能譜了解單體接枝於聚多巴胺的親水性質、表面元素組態和鍵結機制。並藉由綠膿桿菌、大腸桿菌和表皮葡萄球菌細菌貼附，比較不同密度的丙烯醯胺基和甲基丙烯酸接枝於聚多巴胺和具有不同抗生物汙染程度。其中，在XPS結果，於pDA18的塗層上接枝，其效果比於pDA3有更好的單體接枝率。在pDA18 SBAA修飾條件下，表面水接觸角可小於5度；細菌貼附實驗結果，可分別抵抗93%、94.2%和98%的綠膿桿菌、大腸桿菌和表皮葡萄球菌的貼附。最後，利用聚多胺還原銀奈米粒子特性結合抗生物汙染塗層，發展出同時具有銀奈米粒子殺菌功效和SBAA抗細菌貼附的複合式塗層，此表面可抵抗90%大腸桿菌貼附，而貼附於表面的細菌98%為死菌。本研究的最終目的是發展了一種新的修飾方法，可於各種機材表面進行改質而達到抗生物汙染的功能，並且開發多功能生物界面，並期待應用於醫療器材表面塗層，以提升其生物相容性與使用安全性。
;Superhydrophilic zwitterionic materials are recognized as a new class of antifouling materials as an alternative to poly(ethylene glycol) (PEG) for uses of biomedical device in complex conditions. In this study, we aim to develop establish a new grafting method based on polydopamine via Michael addition approach to avoid nonspecific adsorption. The developed coatings exhibit multiple functions, including 1. superhydrophilicity, 2. antifouling properties, 3. substrate-independent modification, 4. facile preparation, and 5. versatility. Dopamine contains both amine and catechol functional groups, which enables to deposit on all kinds of substrates. Sulfobetaine acrylamide (SBAA), Sulfobetaine methacrylate (SBMA) are zwitterionic monomer, which have been demonstrated with their excellent antifouling properties in a polymer brush form. Therefore, the purpose of this work is to graft SB moieties onto polydopamine (pDA) coatings containing abundant amine groups to react with vinyl groups of monomers via the Michael addition to achieve substrate-independent surface modification. We employed three monomers, i.e. SBAA, SBMA, and poly(ethylene glycol) methacrylate (PEGMA) to react with pDA. To develop an antifouling coating, an appropriate preparation strategy is highly determinant for the sufficient grafting density of fouling-resistant groups, i.e. SB and PEG. Surface characterization techniques with the contact angle goniometer, and X-ray photoelectron spectroscopy (XPS) were utilized to explore the surface hydration, chemical states and bonding mechanism of the grafted pDA films. To examine the antifouling properties of the coatings, they were brought to contact with bacteria solutions containing P. aeruginosa, E. coli, and S. epidermidis followed by observing under fluorescence optical microscope. The results indicated that the fouling levels were determined by the grafting densities of monomers on pDA surfaces. In XPS result, pDA18 coating condition grafting densities of monomer is higher than pDA3 coating condition. In pDA18 SBAA coating condition, the contact angle is less than 5 degree. According to the bacterial anti-fouling results, pDA18 SBAA coating can resistance 93%, 94.2% and 98% of P. aeruginosa, E. coli, and S. epidermidis, respectively. This can be modulated by the reaction activities of methacrylate and acrylamide with amine groups on pDA. In addition, silver particles formed in the pDA layers were applied to kill 98% adsorbed bacteria, enabling multiple functions of adlayers. The work paves a new avenue to developing the new functional bioinspired antifouling interface in a substrate-independent fashion. |
