Morimoto Nobuyuki, Segui Florence, Qiu Xing-Ping, Akiyoshi Kazunari, Winnik Françoise M
Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan.
Department of Chemistry and Faculty of Pharmacy, University of Montreal, CP6128 Succursale Centre Ville, Montreal, QC H3C 3J7, Canada.
Langmuir. 2022 May 3;38(17):5218-5225. doi: 10.1021/acs.langmuir.1c02394. Epub 2021 Nov 3.
Thermoresponsive self-assembled nanogels were conveniently prepared by cholesterol end-capped poly(-isopropylacrylamide) (PNIPAM) in water. Both cholesterol end-capped PNIPAMs (telelchelic cholesterol PNIPAM, tCH-PNIPAM) formed flower-like nanogels by the self-assembling of four to five polymer chains with multiple domains of cholesterol in water at 20 °C. Meanwhile, one end-group cholesterol-capped PNIPAM (semitelechelic cholesterol PNIPAM, stCH-PNIPAM) was also formed as a nanogel by the self-assembling of 15-20 polymer chains with 3 to 4 cholesterol domains. The hydrophobic cholesterol domains of tCH-PNIPAM nanogels were maintained above the lower critical solution temperature (LCST) of PNIPAM (>32 °C). Differently, the hydrophobic domains of stCH-PNIPAM were disrupted by cholesterol-free PNIPAM chain ends and formed large mesoglobules above the LCST. These transition controls of hydrophilic end-capped smart polymers may open new methodologies to design thermoresponsive nanosystems.
通过胆固醇封端的聚（N-异丙基丙烯酰胺）（PNIPAM）在水中简便地制备了热响应性自组装纳米凝胶。在20℃下，胆固醇封端的PNIPAMs（遥爪胆固醇PNIPAM，tCH-PNIPAM）通过四到五条带有多个胆固醇结构域的聚合物链在水中自组装形成花状纳米凝胶。同时，一端带有胆固醇封端的PNIPAM（半遥爪胆固醇PNIPAM，stCH-PNIPAM）也通过15 - 20条带有3到4个胆固醇结构域的聚合物链自组装形成纳米凝胶。tCH-PNIPAM纳米凝胶的疏水胆固醇结构域在PNIPAM的低临界溶液温度（LCST）（>32℃）以上得以保持。不同的是，stCH-PNIPAM的疏水结构域被不含胆固醇的PNIPAM链端破坏，并在LCST以上形成大的球状体。亲水性封端智能聚合物的这些转变控制可能为设计热响应性纳米系统开辟新的方法。
