基材表面接枝功能性高分子對細胞培養之影響

Abstract

在生醫材料表面改質(surface modification)領域中，常於基材表面接枝功能性高分子來改變表面性質以達到特定之目的。眾多接枝方式及功能性高分子讓表面改質擁有多樣化之選擇。在本研究中，我們嘗試兩種不同的表面改質組合。 在第一部分研究中，我們利用紫外光起始疊氮基(azide)交聯反應，將熱敏感高分子聚(N-異丙基丙烯酰胺) (poly(N-isopropylacrylamide) (PNIPAAm))接枝於高分子基材上，僅需溫度上之改變即可在避免破壞細胞外基質(extracellular matrix)及表面蛋白情況下取得完整之細胞薄片(cell sheet)。接著利用二甲基矽氧烷(dimethylsiloxane)模具轉印出具有次微米溝脊之聚(N-異丙基丙烯酰胺)表面(寬800奈米、深500奈米)，溝脊表面將引導細胞方性性地排列(alignment)，且此細胞薄片在轉移過程中可保存其方向性。 在第二部分研究中，我們利用化學氣相沉積(chemical vapor deposition)將表面接上馬來酰亞胺(maleimide)官能基，並將兩性離子磺基甜菜鹼甲基丙烯酸酯(sulfobetaine methacrylate)與半胱胺(cysteamine)以不同比例共聚合，透過半胱胺之硫醇(thiol)與馬來酰亞胺之雙鍵(ene)反應將高分子接枝於表面，並利用兩性離子之超親水性達到抗貼附(anti-fouling)之效果，在本研究探討之聚合比例中，於側練上具有較高硫醇官能基比例之高分子能較有效地降低表面上細胞及血小板之貼附量與蛋白質之吸附量。

In surface modification of biomaterials, grafting functional polymers to substrates is one strategy for tailoring surface property to meet the particular demand. It is various approach of conjugation and functional polymers lead to a diversity of surface modification. Here, we try to develop the following two kinds of surface modification. In the first part of study, by a UV-activated azide-based crosslinking mechanism, we immobilized thermo-responsive polymer poly(N-isopropylacrylamide) (PNIPAAm) on plastic substrate. Cell sheets could be harvested by temperature change with an intact extracellular matrix. Next, grooved PNIPAAm substrates were fabricated by imprinting from grooved poly(dimethylsiloxane) (PDMS) molds (800 nm in groove width and 500 nm in depth). C2C12 cells formed aligned cell sheets on the grooved PNIPAAm surface. The aligned cell sheet could be transferred to a gelatin substrate without losing cell alignment. In the second part of study, we deposited double bond-containing maleimide onto substrate by chemical vapor deposition in a substrate independent manner. Also, thiol containing cysteamine were copolymerized with zwitterionic sulfobetaine methacrylate (SBMA) in different molar ratio, and surfaces were modified via thio-ene reaction. Thanks to the superhydrophilicity of SBMA, the modified surfaces possessed good efficacy of anti-fouling. Among the monomer ratios tested in the experiment, the amount of cell adhesion, platelet adhesion and protein adsorption were decreased more profoundly on the surface modified with polymer with higher thiol groups on the side chain.