基于星型杂臂环糊精聚合物的纳米胶束: 构筑及包合特性

通过胺化反应和原子转移自由基聚合(ATRP)，合成了以β-环糊精为“核”，以1条聚乙二醇和2~4条聚N-异丙基丙烯酰胺为“臂”的双亲水性星型杂臂聚合物(MPEG-CD-PNIPAMx)。通过1H NMR,13C NMR和凝胶渗透色谱/多角度激光光散射联用(SEC/MALLS)对其结构进行了表征。对1H NMR峰面积积分计算得聚N-异丙基丙烯酰胺“臂”数为2~4。通过紫外-可见分光光度计测得该星型大分子的较低溶液临界温度(LCST)为37℃。MPEG-CD-PNIPAMx在其水溶液温度达到LCST以上时呈现两亲性，并通过疏水相互作用自组装成以聚N-异丙基丙烯酰胺为“核”，以β-环糊精及聚乙二醇为“壳”的纳米级胶束粒子。通过MPEG-CD-PNIPAMx及其胶束粒子在芘溶液中的荧光光谱，发现胶束粒子对疏水性客体小分子的包合可发生在处于壳层的β-环糊精的疏水性空腔和胶束粒子的疏水性内核。

Construct of Nano Micelles Based on Miktoarm Star Copolymer with a Cyclodextrin Core and Their Inclusion Properties

A star-shaped polymer, MPEG-CD-PNIPAMx, which possesses the lower critical solution temperature (LCST), was designed and synthesised. MPEG-CD-PNIPAMx was composed of a β-cyclodextrin(β-CD) moiety as the core，one Methoxypolyethylene glycol (MPEG) chain and 2~4 poly(N-isopropylacrylamide)(PNIPAM) chains as double hydrophilic arms. The structure of MPEG-CD-PNIPAMx was characterized by 1H NMR, 13C NMR and the molecular weight and molecular weight distribution were measured by size exclusion chromatography/multi-angle laser light scattering(SEC/MALLS) technology. The number of PNIPAM arm was determined by integrating the peaks of 1H NMR spectrum. When the temperature of aqueous solution of MPEG-CD-PNIPAMx raises over the LCST, the star shaped molecule becomes amphiphilic, and then self-assemble into micelles with PNIPAM as the core layer, β-CD and MPEG as the shell layer. The fluorescence spectroscopy of MPEG-CD-PNIPAMx and its micelles in pyrene aqueous solution revealed that the micells can include hydrophobic guest molecule at two sites: the cavity of β-CD and the hydrophobic core of the micelle.