主客体胶束水凝胶的制备及对神经生长因子的包载

通过可逆加成-断裂链转移聚合(RAFT)反应制备了一种亲水性两嵌段聚合物——聚乙二醇/聚N-异丙基丙烯酰胺(PEG-PNIPAM),利用α-环糊精(α-CD)与其中PEG链段的选择性包合形成了一种独特的主客体胶束,这种胶束由于具备中空结构,可对亲水性药物起到很好的负载作用。其对神经生长因子的包载率为经典普朗尼克F127胶束的2倍。进一步利用主客体胶束为大分子交联剂制备丙烯酰胺水凝胶,可赋予水凝胶优异的力学性能,拉伸伸长率为化学交联对照组5倍,并且强度高于对照组2倍以上。循环拉伸测试表明,该水凝胶具有良好的应力耗散机制。

Preparation of Host-Guest Micellar Hydrogels and the Nerve Growth Factor Encapsulation

A hydrophilic two-block polymer chain was prepared by reversible addition-fragmentation chain transfer polymerization(RAFT)with single methyl modified polyethylene glycol(mPEG)and N-isopropyl acrylamide(NIPAM).After PNIPAM ends of the polymer were modified with double bonds,the host and guest interaction between the PEG segment and theα-cyclodextrin(α-CD)formed hydrophobic rigid chain segments,and self-assembled in water to form hollow micelles.The host-guest micelles were compared with the control group of Pluronic F127micelles in the nerve growth factor(NGF)encapsulation test,and the results show that the host-guest micelle encapsulation rate is more than 2times of F127micelles.The host guest micelles were further used as cross-linker to polymerize with acrylamide monomer(AAm)to obtain a super-stretched host guest micelle hydrogel.Themorphology,water content,swelling ratio and mechanical properties of the hydrogel were characterized.The results show that the hydrogel has a porous structure with a water content of 65%and a swelling rate of 811%.The hydrogel also show a super strong tensile property,the elongation at break is more than 20times,and the strength is more than 2times higher than the control group,and the cyclic tensile test shows that the hydrogel has a good stress dissipation mechanism.