Huo Dongxia, Li Yana, Qian Qingwen, Kobayashi Takaomi
School of Materials Engineering, Zhengzhou University, Zhengzhou 450052 Henan, PR China.
Colloids Surf B Biointerfaces. 2006 Jun 1;50(1):36-42. doi: 10.1016/j.colsurfb.2006.03.020. Epub 2006 Apr 7.
Monodispersed poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM/AAc) microgels with various contents of acrylic acid (AAc) and cross-linker N,N'-methylenebisacrylamide (MBAAm) were synthesized by surfactant-free emulsion polymerization. The microgels exhibited affinity of binding bovine serum albumin (BSA) with increase of AAc contents. The adsorption amount of BSA was strongly dependent on suspension pH. The maximum adsorption was observed at around pH 4.0, while both low pH and basic conditions induced the rather low adsorption. In addition, AFM images showed that the microgel particles underwent bridging aggregation by loading BSA. The resultant BSA-microgel particles became more hydrophobic after loading BSA. Importantly, the adsorption of BSA onto PNIPAM/AAc microgel was found to alter the swelling/deswelling behavior of the resultant microgel suspensions. With the increase of BSA concentration, the volume phase transition temperature of BSA-microgel particles shifted to the lower temperature.
通过无表面活性剂乳液聚合合成了具有不同丙烯酸（AAc）含量和交联剂N,N'-亚甲基双丙烯酰胺（MBAAm）的单分散聚（N-异丙基丙烯酰胺-共-丙烯酸）（PNIPAM/AAc）微凝胶。随着AAc含量的增加，微凝胶表现出结合牛血清白蛋白（BSA）的亲和力。BSA的吸附量强烈依赖于悬浮液的pH值。在pH约4.0时观察到最大吸附量，而低pH和碱性条件下的吸附量相当低。此外，原子力显微镜图像显示，负载BSA后微凝胶颗粒发生了桥连聚集。负载BSA后，所得的BSA-微凝胶颗粒变得更疏水。重要的是，发现BSA在PNIPAM/AAc微凝胶上的吸附改变了所得微凝胶悬浮液的溶胀/去溶胀行为。随着BSA浓度的增加，BSA-微凝胶颗粒的体积相变温度向较低温度移动。
