Iwasaki Yasuhiko, Takamiya Mika, Iwata Ryoko, Yusa Shin-Ichi, Akiyoshi Kazunari
Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Tokyo, Japan.
Colloids Surf B Biointerfaces. 2007 Jun 15;57(2):226-36. doi: 10.1016/j.colsurfb.2007.02.007. Epub 2007 Feb 11.
To improve interfacial phenomena of poly(dimethylsiloxane) (PDMS) as biomaterials, well-defined triblock copolymers were prepared as coating materials by reversible addition-fragmentation chain transfer (RAFT) controlled polymerization. Hydroxy-terminated poly(vinylmethylsiloxane-co-dimethylsiloxane) (HO-PV(l)D(m)MS-OH) was synthesized by ring-opening polymerization. The copolymerization ratio of vinylmethylsiloxane to dimethylsiloxane was 1/9. The molecular weight of HO-PV(l)D(m)MS-OH ranged from (1.43 to 4.44)x10(4), and their molecular weight distribution (M(w)/M(n)) as determined by size-exclusion chromatography equipped with multiangle laser light scattering (SEC-MALS) was 1.16. 4-Cyanopentanoic acid dithiobenzoate was reacted with HO-PV(l)D(m)MS-OH to obtain macromolecular chain transfer agents (macro-CTA). 2-Methacryloyloxyethyl phosphorylcholine (MPC) was polymerized with macro-CTAs. The gel-permeation chromatography (GPC) chart of synthesized polymers was a single peak and M(w)/M(n) was relatively narrow (1.3-1.6). Then the poly(MPC) (PMPC)-PV(l)D(m)MS-PMPC triblock copolymers were synthesized. The molecular weight of PMPC in a triblock copolymer was easily controllable by changing the polymerization time or the composition of the macro-CTA to a monomer in the feed. The synthesized block copolymers were slightly soluble in water and extremely soluble in ethanol and 2-propanol. Surface modification was performed via hydrosilylation. The block copolymer was coated on the PDMS film whose surface was pretreated with poly(hydromethylsiloxane). The surface wettability and lubrication of the PDMS film were effectively improved by immobilization with the block copolymers. In addition, the number of adherent platelets from human platelet-rich plasma (PRP) was dramatically reduced by surface modification. Particularly, the triblock copolymer having a high composition ratio of MPC units to silicone units was effective in improving the surface properties of PDMS. By selective decomposition of the Si-H bond at the surface of the PDMS substrate by irradiation with UV light, the coating region of the triblock copolymer was easily controlled, resulting in the fabrication of micropatterns. On the surface, albumin adsorption was well manipulated.
为改善聚二甲基硅氧烷（PDMS）作为生物材料的界面现象，通过可逆加成-断裂链转移（RAFT）可控聚合制备了结构明确的三嵌段共聚物作为涂层材料。通过开环聚合合成了羟基封端的聚（乙烯基甲基硅氧烷-共-二甲基硅氧烷）（HO-PV(l)D(m)MS-OH）。乙烯基甲基硅氧烷与二甲基硅氧烷的共聚比为1/9。HO-PV(l)D(m)MS-OH的分子量范围为(1.43至4.44)×10⁴，通过配备多角度激光光散射的尺寸排阻色谱（SEC-MALS）测定其分子量分布（M(w)/M(n)）为1.16。4-氰基戊酸二硫代苯甲酸酯与HO-PV(l)D(m)MS-OH反应得到大分子链转移剂（macro-CTA）。2-甲基丙烯酰氧基乙基磷酰胆碱（MPC）与macro-CTA进行聚合。合成聚合物的凝胶渗透色谱（GPC）图为单峰，且M(w)/M(n)相对较窄（1.3 - 1.6）。然后合成了聚（MPC）（PMPC）-PV(l)D(m)MS-PMPC三嵌段共聚物。通过改变聚合时间或进料中macro-CTA与单体的组成，三嵌段共聚物中PMPC的分子量易于控制。合成的嵌段共聚物在水中微溶，在乙醇和异丙醇中极易溶解。通过硅氢加成进行表面改性。将该嵌段共聚物涂覆在经聚（氢甲基硅氧烷）预处理的PDMS薄膜上。通过用嵌段共聚物固定，有效改善了PDMS薄膜的表面润湿性和润滑性。此外，表面改性显著减少了来自人富血小板血浆（PRP）的黏附血小板数量。特别地，MPC单元与硅氧烷单元组成比高的三嵌段共聚物在改善PDMS的表面性能方面有效。通过用紫外光照射选择性分解PDMS基底表面的Si-H键，可轻松控制三嵌段共聚物的涂层区域，从而制备微图案。在表面上，白蛋白吸附得到了很好的控制。
