基于主客体识别的温度及氧化还原双重响应型磁性聚合物胶束

Temperature and redox dual-responsive magnetomicelles based on host-guest identification

制备磁性纳米粒子和聚合物的复合材料是研究热点,而如何简单高效地构建磁性纳米粒子和聚合物的复合体系是目前研究的难点.基于此,本研究首先分别制备主体分子CD-MNPs和客体分子m PEG-Fc及PNIPAM-Fc,利用β-CD和二茂铁基团之间的主客体识别作用,在磁性纳米粒子表面构筑两种亲疏水性不同的聚合物链,通过控制温度的变化,使其在水中发生组装,同时通过氧化还原电位的变化,实现组装体系形成和瓦解的可逆变化.并对得到的胶束进行了载药性能的表征.TEM和DLS的结果显示得到了粒径大概为250 nm的磁性聚合物胶束,并可以通过温度和氧化还原的变化实现胶束的形成和瓦解,而且这种胶束可以作为药物载体,其对抗癌药物阿霉素(Dox)的包封率高达73%.综上,本研究得到了一种兼具温度和氧化还原敏感的磁性聚合物胶束,这种新型的胶束在药物释放和磁共振成像方面具有潜在的应用前景.

This study aimed to develop an effective and simple magnetic-polymer assembly system. β-CD covered Fe3O4 magnetic nanoparticles （CD-MNPs） was prepared as host molecule while ferrocene terminated polymer polyethylene glycol （mPEG-Fc） and poly（N-isopropylacrylamide） （PNIPAM-Fc） were prepared as guest molecule. Then PEG-Fc and PNIPAM-Fc were attached on the surface of nano magnetic crystal through the host-guest inclusion between ferrocene groups （Fc） and β-CD. The resulting MNPs became amphiphilic in water when the temperature was raised above the LCST of PNIPAM and could be self-assembled into micelles with size around 250 nm, which was characterized by TEM and DLS. Meanwhile, these micelles could disassemble into stable small MNPs after addition of oxidizing agents, and could be formed again after addition of reducing agents. Moreover, the magnetic micelles could serve as a drug carrier with the encapsulation efficiency up to 73% for DOX. Therefore, a novel magnetic micelles with thermal- and redox-responsiveness is obtained, which shows great potential in drug delivery, MRI contrast, and hyperthermia treatment.