為改善鈦及其合金之醫療器材在血液相容性及抗生物聚集(anti-biofouling) 能力不佳的問題。本研究主要是希望能夠發展新型表面改植的技術來改善其血液相容性的問題，在研究中我們合成一雙功能性共聚高分子，該高分子同時具備有可穩固鍵結於鈦基材表面以及提供鈦基材表面良好血液相容性的能力。在單體的選擇上，選擇含有亞磷酸官能基的6-acryloyloxy hexyl phosphonic acid (AcrHPA) 以及帶雙電性官能基之sulfobetaine methacrylate (SBMA)。將兩單體透過傳統自由基聚合的方式合成雙功能性共聚高分子，該共聚高分子主要透過側鏈上亞磷酸官能基鍵結於鈦基材表面，藉由雙電性硫代甜菜鹼官能基則提供該高分子良好的生物惰性，將進而達到預期之修飾效果。
在研究中藉用NMR、GPC、TGA對共聚物進行組成以及基本性質之鑑定，爾後將製備好之共聚高分子以旋轉塗布的方式塗佈於鈦基材上加熱進行表面鍵結反應，接著利用表面接觸角 (contact angle)、原子力顯微鏡(atomic force microscopy)、電子能譜儀 (x-ray photoelectron spectroscopy)以及血小板吸附實驗 (in vitro platelets adhesion)探討其改質層表面之親疏水性、表面粗糙度、膜厚、表面元素組成以及血液相容性。
綜合各實驗分析可知6-acryloyloxy hexyl phosphonic acid 以及sulfobetaine methacrylate 兩單體可透過傳統自由基聚合的方式產生共聚合物，且可透過Kelen-Tudös method 可得兩單體之競聚率分別為rAcrHPA = 0.726 rSBMA= 0.826，由兩單體之競聚率可推測該共聚高分子主要是以隨機排列的方式存在。將完成鍵結之改植層經多次清洗後，由表面接觸角以及電子能譜儀之結果可得知共聚高分子已成功透過化學鍵結的方鍵結於鈦基材表面，且各改植層之表面親疏水性以及表面粗糙度隨著各共聚高分子之組成有所變化。經由血小板吸附實驗我們可以發現當進料比AcrHPA以及SBMA 3：7 時該改質層表面有最佳的血液相容性。

Despite of its widely commercial applications in biomedical area, the titanium-based material still face the challenges of hemocompatibility and anti-biofouling. The objective of this investigation was to develop a novel surface modification strategy for titanium-based material to improve thromboresistance for surfaces in rigorous blood-contacting cardiovascular applications. In this work, a novel multi-functional copolymer, which composed of both 6-acryloyloxy hexyl phosphonic acid (AcrHPA) and sulfobetaine methacrylate (SBMA) units will be synthesized by traditional free radical copolymerization. Various copolymers bearing phosphonic acid groups, which are able to bind to titanium surfaces, and zwitterionic groups, that can inhibit plasma protein adsorption, blood platelet adhesion and activation, and thrombus formation in vitro, were synthesized. These copolymers should be able to bind to titanium by means of the phosphonic acid groups to form a stable blood-inert surface.
The properties of these copolymers were characterized with nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and thermogravimetric analyzer (TGA). The copolymer was then spin-coated onto the titanium substrate and heated for the formation of a covalent-bound surface layer. The surface hydrophilicity, morphology and chemical characteristics of these layers were examined by contact angle measurements (CA), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS). Furthermore, the hemocompatibility of polymer films was characterized through in vitro platelets adhesion testing.
Various novel copolymers possessing zwitterionic group and being able to bind to titanium surface were synthesized successfully. By determination of the copolymerization parameters (rAcrHPA = 0.726 and rSBMA= 0.826) with Kelen-Tudös method, the copolymerization reaction is like an ideal statistical reaction with a slight tendency for adding the monomers in a random order. CA and XPS measurement indicated a covalent bound layer of AcrHPA-SBMA copolymer was formed. In addition, the surface characteristics of the titanium-bound copolymer were affected by the composition of the monomers used. Through platelets adhesion experiment in vitro, we have noted that the copolymer prepared by the monomer feeding ratio of AcrHPA : SBMA= 3:7 showed the highest hemocompatibility among all samples examined. This work provided a practical method to create a stable blood-inert surface on titanium-based material by simply grafting a copolymer with both zwitterionic and phosphonic acid functionalities.

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