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  • 學位論文

新型兩性雙離子性4-乙烯基吡啶羧基甜菜鹼刷狀高分子於生物惰性晶片之設計

Novel design of bio-inert sensor chips grafted with zwitterionic 4-vinylpyridine carboxybetaine polymer brushes

指導教授 : 嚴大任 張雍

摘要


抗沾粘技術廣泛使用在生物及工程上的應用已經超過二十年,從隱形眼鏡到船舶塗料都能見到其蹤跡。近年來,藉由模仿細胞膜組成的結構,由正電及負電集團所形成的雙離子材料可以透過靜電作用力與水分子產生強烈的鍵結並形成水合層,因此能夠擁有高度的抗蛋白吸付並同時具有良好的血液相容性,這些特性使得雙離子材料在眾多抗沾粘材料中展現極大的潛力。然而,利用雙離子材料改質過後的材料表面變得非常親水,而該親水表面在空氣中會擁有較高的表面能,這將使材料表面容易吸附髒污。因此,在抗沾粘領域中,科學家致力於發展一個具有能在氣相中穩定並同時能達到超低蛋白質吸附特性的雙離子材料。 在此研究中,我們成功合成具有雙離子特性的4-乙烯基吡啶羧基甜菜鹼,且利用表面起始自由基轉移聚合法將其成功接枝在材料表面上。除此之外,我們藉由表面電漿共振量測定量描述所合成分子的抗吸付能力,並藉由調控像是單體濃度及溶劑的離子強度等合成參數,使得該分子可達最佳7.5 ng/cm2超低蛋白質吸附的程度。更進一步,在血液貼附測試中,我們亦得到材料表面同樣具有抵抗血小板及血球的貼附的特性,確認該分子的生物惰性。最後,具有雙離子特性的4-乙烯基吡啶羧基甜菜鹼表面在水相環境中的油相接觸角約130度,與一般熟知的雙離子性甜菜鹼表面相仿,此結果也解釋了兩者表面在水相環境中抗蛋白質吸付的特性。另一方面,此雙離子表面在氣相環境中的水接觸角約為80度,明顯高出一般熟知的雙離子性甜菜鹼表面(約6度),顯示出其有較低的表面自由能,而能在氣相中有較穩定的特性。 總結以上,我們成功設計並合成出此新穎的雙離子性4-乙烯基吡啶羧基甜菜鹼,且成功將此材料接枝於材料表面,與一般熟知的雙離子材料甜菜鹼表面相比,此晶片表面不僅擁有良好的生物惰性,也擁有較高的氣相穩定性,可被使用在更多應用上。

並列摘要


Antifouling technique has been developed for over two decades and used in many biomedical and engineering applications ranging from contact lenses to marine coating. Among so many different antifouling materials, zwitterionic antifouling materials attract growing attentions around the world because their prefect protein-resistance and hemocompatibility. The structure of zwitterionic materials, bio-inspired from cell membranes, is similar to phosphatidylcholine, which contains positive and negative charges and thus can strongly bind with water molecules and form a hydration layer by electrostatically induced interaction, resulting in highly resistant to protein adsorption. Yet, a zwitterionic-polymer modified surface will become too hydrophilic and promote dirt adhesion or surface contamination much easier in air; herein, there appears a great demand on developing an air-stable zwitterionic material. On the other hand, to develop such zwitterionic material should achieve super-low fouling level as well. To approach these two requirements, in this work, we successfully synthesize and characterize a new zwitterionic material, zwitterionic 4-vinylpyridine carboxybetaine (z4VP) and then grafted zwitterionic poly(4-vinylpyridine carboxybetaine) (zP4VP) brushes from a gold surface via surface-initiated atom transfer radical polymerization (SI-ATRP) to reduce nonspecific protein adsorption and blood cell attachment. Besides, by changing different parameters of SI-ATRP such as a monomer concentration and ionic strength of a solvent, we obtained the optimized conditions for antifouling performance of the zP4VP system. In addition, to measure protein adsorption, we employ surface plasmon resonance (SPR) and the results suggest that the zP4VP surface can indeed reduce protein adsorption down to 7.5 ng/cm2, a super-low fouling level. The consistent results of platelets and blood cell attachment on the zP4VP surface observed by a confocal laser scanning microscopy (CLSM) are also provided to further confirm the antifouling performance of the zP4VP surface. Further, an oil contact angle of both the zP4VP surface and well-known poly(sulfobetaine methacrylate) (PSBMA) surface in the water is around 130 degrees which reveals a low interfacial energy in the water and explains their high hydrophilicity to resist protein adsorption. On the other hand, the zP4VP surface with a water contact angle (CA) around 80 degrees indicates the surface energy of the zP4VP surface is lower than the PSBMA surface (~6 degree) in the air. As a result, we claim that the zP4VP surface indeed exhibits the air-stable property. With the abovementioned properties of the z4VP, we summarize that the zP4VP surface not only exhibits a similar antifouling capability compared to the PSBMA surface in the water but also possesses relatively higher air-stable characterization than the PSBMA surface evidenced by both SPR and CA measurement.

參考文獻


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