Ishihara K, Nomura H, Mihara T, Kurita K, Iwasaki Y, Nakabayashi N
Division of Organic Materials, Tokyo Medical and Dental University, Japan.
J Biomed Mater Res. 1998 Feb;39(2):323-30. doi: 10.1002/(sici)1097-4636(199802)39:2<323::aid-jbm21>3.0.co;2-c.
The amount of plasma protein adsorbed on a phospholipid polymer having a 2-methacryloyloxyethyl phosphorylcholine (MPC) moiety was reduced compared to the amount of protein adsorbed onto poly[2-hydroxyethyl methacrylate (HEMA)], poly[n-butyl methacrylate (BMA)], and BMA copolymers with acrylamide (AAm) or N-vinyl pyrrolidone (VPy) moieties having a hydrophilic fraction. To clarify the reason for the reduced protein adsorption on the MPC polymer, the water structure in the hydrated polymer was examined with attention to the free water fraction. Hydration of the polymers occurred when they were immersed in water. The differential scanning calorimetric analysis of these hydrated polymers revealed that the free water fractions in the poly(MPC-co-BMA) and poly(MPC-co-n-dodecyl methacrylate) with a 0.30 MPC mole fraction were above 0.70. On the other hand, the free water fractions in the poly(HEMA), poly(AAm-co-BMA), and poly(VPy-co-BMA) were below 0.42. The conformational change in proteins adsorbed on the MPC polymers and poly(HEMA) were determined using ultraviolet and circular dichroism spectroscopic measurements. Proteins adsorbed on poly(HEMA) changed considerably, but those adsorbed on poly(MPC-co-BMA) with a 0.30 MPC mole fraction differed little from the native state. We concluded from these results that fewer proteins are adsorbed and their original conformation is not changed on polymer surfaces that possess a high free water fraction.
与吸附在聚甲基丙烯酸2-羟乙酯（HEMA）、聚甲基丙烯酸正丁酯（BMA）以及含有亲水性部分的BMA与丙烯酰胺（AAm）或N-乙烯基吡咯烷酮（VPy）的共聚物上的蛋白量相比，吸附在具有2-甲基丙烯酰氧基乙基磷酰胆碱（MPC）部分的磷脂聚合物上的血浆蛋白量有所减少。为了阐明MPC聚合物上蛋白吸附减少的原因，我们关注自由水分数，研究了水合聚合物中的水结构。将聚合物浸入水中时会发生水合作用。对这些水合聚合物进行差示扫描量热分析表明，MPC摩尔分数为0.30的聚（MPC-co-BMA）和聚（MPC-co-甲基丙烯酸正十二烷基酯）中的自由水分数高于0.70。另一方面，聚（HEMA）、聚（AAm-co-BMA）和聚（VPy-co-BMA）中的自由水分数低于0.42。使用紫外和圆二色光谱测量法测定了吸附在MPC聚合物和聚（HEMA）上的蛋白质的构象变化。吸附在聚（HEMA）上的蛋白质发生了相当大的变化，但吸附在MPC摩尔分数为0.30的聚（MPC-co-BMA）上的蛋白质与天然状态几乎没有差异。从这些结果我们得出结论，在具有高自由水分数的聚合物表面上，吸附的蛋白质较少且其原始构象未发生改变。
