| 摘要: | 熱塑性聚氨酯 (Thermoplastic polyurethane, TPU)是常見的生醫植入材料，具有優秀的生物相容性及機械性質。然而，TPU導管表面的高摩擦係數造成潤滑不足，嚴重影響病患的健康狀態。TPU的疏水性表面更易於吸引蛋白質與細菌的貼附，導致生醫材料長期使用下的不穩定與效能衰退。
為了克服這些缺點，我們選擇2-甲基丙烯醯氧乙基磷酸膽鹼 (MPC) ，以高生物相容性、親水性與防汙性質聞名的雙離子單體，應用於TPU表面改性。然而，礙於TPU表面的惰性與疏水性質，將親水性的MPC修飾並固定於TPU表面仍是一大挑戰。在本研究中，採用了帶有二苯甲酮基團的單體3-甲基丙烯醯氧基-2-羥基丙基-4-氧二苯甲酮 (MHPBP)。透過可逆加成-斷裂鏈轉移 (RAFT) 反應合成嵌段共聚物Poly (MPC-b-MHPBP)，經由簡易的浸塗處理對TPU導管進行了表面修飾。高分子鏈中的疏水結構MHPBP能透過二苯甲酮基團抓取TPU表面的氫原子，進行烴基插入交聯反應 (CHic) 將共聚物固定於TPU基材表層，將TPU導管修飾成親水潤滑的的表面。共聚物通過核磁共振氫譜 (1H NMR) 確認其組成與轉化率，再透過溶解度試驗決定適用的塗層用溶劑。塗層溶液由黏度計、表面張力計與紫外-可見光分光光譜儀分析其黏度、表面張力與透明度等物理性質。共聚物通過浸塗法沉積，在吸收UV光源的輻射能量後，在TPU導管表面進行光接枝反應。完成表面修飾後，使用全反射-傅立葉轉換紅外線光譜儀 (ATR-FTIR) 及X射線光電子能譜儀 (XPS) 確認雙離子共聚物 Poly (MPC-b-MHPBP) 與導管表面的鍵結；塗層的親水性由水接觸角測量驗證，並透過拉伸機進行摩擦試驗測量潤滑效果；進行細菌與蛋白質貼附實驗以檢驗導管表面的防汙性能；最後使用原子力顯微鏡 (AFM) 與掃描式電子顯微鏡 (SEM) 觀察薄膜表面型態與粗糙度。
本研究中，透過簡易的改質方式，將雙離子共聚物Poly (MPC-b-MHPBP)修飾於TPU表面，使導管表面具有良好的潤滑與防汙性能。得益於簡單而快速的塗佈程序，該光起始型MPC嵌段共聚物有望作為一種有效的表面改性材料應用於醫療器材領域。
;Thermoplastic polyurethane (TPU), is a common biomedical implant. However, the high friction and deficient lubrication of TPU catheters have a direct influence on the health status of each patient. Its hydrophobic surface also attracts bacterial adhesion and protein adsorption, resulting in long-term instability and failure of biomaterials.
To overcome these disadvantages, 2-methacryloyloxyethyl phosphorylcholine (MPC) which is known as a biocompatible, hydrophilic and antifouling monomer, was adopted in TPU surface modification. Nevertheless, immobilization of MPC on TPU remains a challenge. Due to the inertness and hydrophobicity of TPU, hydrophilic MPC was found difficult to adhere on TPU. In this study, benzophenone monomer 3-methacryloyloxy-2-hydroxypropyl-4-oxybenzophenone (MHPBP) was developed. Diblock copolymer Poly (MPC-b-MHPBP) was synthesized via reversible addition-fragmentation chain transfer (RAFT) to modify TPU catheter via a simple dip coating process. MHPBP in the copolymer with hydrophobic domain was able to bind the copolymer to adjacent C-H groups on TPU surfaces via C, H insertion crosslinking (CHic) on the benzophenone group. The polymers were characterized by 1H nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and solubility test. The coating solutions were analyzed by viscometer, surface tension, and UV-vis for transparency. The polymers were deposited via dip coating and photo-grafted on TPU tubes upon UV irradiation. The hydrophilicity of films was accessed by contact angle goniometer. The lubrication of modified TPU tube was measured by friction test using tensile machine. The immobilization of polymer on TPU substrate was studied with x-ray photoelectron spectroscopy (XPS). The roughness and morphology of coating films was characterized with atomic force microscopy (AFM). The antifouling properties were examined by bacterial adsorption test and protein adhesion test. In preliminary data, we found that the modified TPU surfaces became more hydrophilic, therefore provided good antifouling characteristic. Due to the simple, quick coating process, the photoreactive MPC-based diblock copolymer could be used as an efficient surface modifier. |
