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通过原子转移自由基聚合(ATRP)合成了以胆固醇为端基的两亲性聚(N-异丙基丙烯酰胺)(Chol-PNIPAAm),利用FTIR、1H-NMR和GPC等方法表征了聚合物的结构.将该两亲性温敏聚合物与聚乙二醇单甲醚硬脂酸酯(mPEG-SA)通过简单混合,即可得到稳定的Chol-PNIPAAm/mPEG-SA混合胶束体系.与细胞膜中胆固醇通过嵌入磷脂疏水层达到稳定细胞膜的现象类似,Chol-PNIPAAm的胆固醇和mPEG-SA的硬脂酸共同构成了复合胶束的疏水内核,使得混合胶束具有更低的临界胶束浓度(CMC).动态光散射(DLS)研究表明,混合胶束不仅更稳定,而且具有温度响应性,其粒径在33～35℃之间可逆转变.药物体外释放结果表面,温度的升高会导致药物释放加快,PNIPAAm含量越高,释放速度越大.
Cholesterol-terminated amphiphilic poly (N-isopropylacrylamide) (Chol-PNIPAAm) was synthesized by Atom Transfer Radical Polymerization (ATRP). The polymer was characterized by FTIR, 1H- The amphiphilic temperature-sensitive polymer and polyethylene glycol monomethyl ether stearate (mPEG-SA) were mixed by simple mixing to obtain a stable Chol-PNIPAAm / mPEG-SA mixed micellar system. Similar to the fact that cholesterol in the cell membrane stabilizes the cell membrane by intercalating the hydrophobic layer of the phospholipid, the cholesterol of Chol-PNIPAAm and the stearic acid of mPEG-SA together form the hydrophobic core of the composite micelle, resulting in a lower critical micelle (CMC) .The dynamic light scattering (DLS) study shows that the mixed micelles are not only more stable, but also have temperature responsiveness, and the particle size reversibly changes from 33 to 35 ° C. The release of drug on the surface and the increase of temperature Will lead to faster drug release, the higher the PNIPAAm content, the greater the release rate.