Cheng Si-Xue, Zhang Jian-Tao, Zhuo Ren-Xi
Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
J Biomed Mater Res A. 2003 Oct 1;67(1):96-103. doi: 10.1002/jbm.a.10062.
A series of temperature-sensitive poly(N-isopropylacrylamide) (PNIPA) hydrogels with large pore size and fast response were prepared by carrying out polymerizations in aqueous sodium chloride solutions with different concentrations. In comparison with conventional PNIPA hydrogels, the PNIPA gels thus prepared have remarkably larger swelling ratios below their lower critical solution temperature (LCST), and exhibit much faster response rates as the temperature is raised above their LCST. The improved properties are due to the presence of inorganic salt, NaCl, which leads the phase separation and formation of a heterogeneous porous structure during the polymerizations. The study on the drug release properties shows the macroporous hydrogels exhibit modulated release in response to temperature. The model protein, bovine serum albumin (BSA), can be released completely from the porous hydrogels at the temperature lower than the LCST because the pore size of the hydrogels is larger than the protein molecules. However, the release of BSA from the gels almost stops after a "burst" release in the initial stage at the temperature higher than the LCST because the pores are closed at the high temperature.
通过在不同浓度的氯化钠水溶液中进行聚合反应，制备了一系列具有大孔径和快速响应的温度敏感型聚（N-异丙基丙烯酰胺）（PNIPA）水凝胶。与传统的PNIPA水凝胶相比，如此制备的PNIPA凝胶在其较低临界溶液温度（LCST）以下具有显著更大的溶胀率，并且当温度升高到其LCST以上时表现出更快的响应速率。这些改进的性能归因于无机盐NaCl的存在，其在聚合过程中导致相分离并形成异质多孔结构。对药物释放性能的研究表明，大孔水凝胶表现出对温度的调节释放。模型蛋白牛血清白蛋白（BSA）在低于LCST的温度下可以从多孔水凝胶中完全释放，因为水凝胶的孔径大于蛋白质分子。然而，在高于LCST的温度下，BSA从凝胶中的释放在初始阶段的“突释”后几乎停止，因为孔在高温下关闭。
