pH及温度双重敏感性纳米粒水凝胶的制备及表征

Synthesis and characterization of pH and temperature-sensitive nano-hydrogels

目的:制备具有pH及温度双重敏感性的纳米水凝胶,并使其粒径控制在100nm以下。方法:利用聚合沉淀法合成聚N-异丙基丙烯酰胺(PNIPA)及聚(N-异丙基丙烯酰胺-丙烯酸)(PNIPA-co-AA)纳米水凝胶。通过马尔文粒度仪与透射电子显微镜考察了纳米水凝胶的粒径分布,并以500nm处的透光率表征了PNIPA与PNIPA-co-AA的低临界溶解温度(LCST)和pH敏感特性。结果:通过调节表面活性剂十二烷基硫酸钠(SDS),得到了25～250nm不同粒径大小的纳米水凝胶;PNIPA-co-AA的LCST与参与共聚的丙烯酸单体有关,其LCST可由34℃(PNIPA的LCST)提高至35～45℃;同时PNIPA-co-AA对pH具有较好的敏感性。结论:PNIPA-co-AA纳米水凝胶有望成为智能型控释和靶向性药物载体。

Aim： To synthesize pH and temperature-sensitive nano-hydrogels with diameter less than 100 nm. Methods： Poly （N-isopropylacrylamide） （PNIPA） nano-hydrogel and its derivative poly （ N-isopropylacrylamide-co- acrylic acid）（PNIPA-co-AA） nano-hydrogels were synthesized by precipitation polymerization and the size was measured by laser particle size analyzer and transmission electron microscopy. Transmittance at 500 nm was utilized to characterize pH and temperature sensitivity of nano-hydrogels. Results：In the presence of different amount of sodium dodecylsulfate, nano-hydrogels with diameters ranging from 25 um to 250 um have been obtained. PNIPA-co-AA nanoparticles with lower critical solution tempemture（LCST） ranging from 35 ℃ to 45 ℃ were correlated to molar fraction of acrylic acid copolymerized with NIPA. PNIPA-co-AA nano-hydrogels also responded to pH stimulus, which was related to pKa of AA. Conclusion：PNIPA-CO-AA nano-hydrogels are promising candidates for novel thug carriers with advantages of controlled release and targeting effect.