基于超支化聚合物的单分子胶束的研究进展

近年来,单分子胶束/粒子(Unimolecular micelle:UIM)引起了人们的极大兴趣,这是由于通过对核和壳的化学设计,粒子的溶解性、生物相容性、刺激响应性、与基质的相互作用等都可得到改进,粒子还可以包裹多种客体。相对于自组装法而言,超支化聚合物法在合成UIM方面具有某些独有的特征,主要表现在:(1)UIM的尺寸主要由超支化聚合物决定,从而具有相当的可预见性;(2)可以大规模、高浓度合成UIM;(3)对聚合物的亲水性没有要求,可以利用的聚合物非常广泛,核-壳结构更为丰富;(4)产品可以以任何形式存在。本文在简要比较以自组装法和超支化聚合物法合成UIM的基础上,主要介绍了以超支化聚合物(特别是超支化聚甘油醚(PG))为支架合成各种核-壳聚合物及其应用。以长链小分子或聚合物改性的PG可以用作纳米胶囊,也可以作为纳米模板来合成各种无机粒子,而后者显示出量子限制效应和模板效应。特别地,一种全亲水壳交联的、刺激响应的粒子的合成显示了超支化聚合物法在合成复杂UIM方面的优势。总之,超支化聚合物法提供了巨大的核-壳结构分子设计空间,为合成功能集成粒子提供了更多机会。

Unimolecular Micelle Based on Hyperbranched Polymer

Unimolecular micelle(UIM) has evoked much interest recently because a variety of guests can be effectively encapsulated,and an improved solubility,biocompatibility,stimuli-responsive ability,and interaction with a matrix could be obtained via the chemical design of the core and shell.Compared with the self-assembly route,the route employing hyperbranched polymer shows such features as(1) the UIM size is mainly determined by the hyperbranched polymer,thus with good predictability;(2) can be synthesized in large-scale and under high concentration;(3) wide availability of polymer and richness in core-shell structure because the synthesis is independent of the hydrophility of the polymers;(4) the resulting product can exist as a solid.This review concisely compares the two routes,and mainly summaries the synthesis and resulting property of a variety of UIMs,with an emphasis on hyperbranched polyglycerol(PG).PG modified with long chain small molecules or polymers can be used as a nanocapsule,or as a nanotemplate for the synthesis of inorganic nanoparticles,the resulting inorganic nanoparticles can show quantum-confined effect and template effect.Specially,the synthesis of a wholly hydrophilic,shell-crosslinked,stimuli-responsive nanoparticle shows the advantage of the hyperbranched-polymer-route.Generally speaking,this route provides a wider room for molecular design of UIMs,and thus extends the accessibility of multifunctional nanoparticles.