细胞内氧化还原响应型肝靶向嵌段聚合物的合成及纳米自组装性能

摘要

The amphiphilic block copolymers PMAIgGP-b-PPDSMA(PMgPP)with a hydrophilic block containing galactose side groups and a hydrophobic segment containing pyridine ring disulfide pendant groups were prepared by two-step reversible addition-fragmentation chain transfer(RAFT)polymerization and acetal deprotection reaction.Their well-defined chemical structures were confirmed by proton nuclear magnetic resonance(1 H NMR)and gel permeation chromatography(GPC).Core-crosslinked PMgPP nanoparticles(PMgPP-CC NPs)were prepared by nano-precipitation technology and thiol oxidation self-crosslinking reaction.Dynamic light scattering(DLS)and transmission electron microscopy(TEM)were used to determine the size of PMgPP-CC NPs(＜30 nm)and the particle size distribution indexes were narrow.Under the reduc-tion environment of GSH,the particle sizes of PMgPP-CC NPs were increasing with incubation time,indica-ting the disassembly of PMgPP-CC NPs.PMgPP-CC/DOX NPs were prepared by DOX as the model drug,and drug loading content up to 12.5% and entrapment efficiency of 83.3%.The particle sizes were similar to that of the corresponding blank CC NPs,and the particle size distribution was uniform.Within 46 h in vitro,4.47% of DOX was released from the PMgPP-CC/DOX NPs in normal physiological conditions,whereas 50.6% was released in the presence of 10 mmol/L GSH condition analogous to the reductive microenvironment in cytoplasm.The cell uptake tests further confirmed that PMgPP-CC/DOX NPs could be efficiently released in the HepG-2 cells.3-(4,5-dimethyethiazol-2-yl)-2,5-diphemptetrazolium bromide(MTT)assays show that PMgPP-CC/DOX NPs has good proliferation inhibitory activity against HepG-2 cells.Therefore,multifunction-al PMgPP-CC NPs have a good prospect in the field of precise hepatoma-targeting drug delivery.%通过两步可逆加成-断裂链转移自由基聚合(RAFT)和缩醛脱保护反应合成了一种亲水段含半乳糖侧基和疏水段含吡啶环二硫键侧基的两亲性嵌段聚合物 PMAIgGP-b-PPDSMA(PMgPP),用核磁共振氢谱(1H NMR)和凝胶渗透色谱(GPC)分析验证了目标产物的化学结构.利用纳米沉淀技术和巯基氧化自交联反应制备内核二硫键交联的PMgPP纳米粒(PMgPP-CC NPs).动态光散射(DLS)和透射电子显微镜(TEM)测定结果表明,PMgPP-CC NPs粒径较小(＜30 nm),且粒径分布较窄.在谷胱甘肽(GSH)还原环境下,PMgPP-CC NPs粒径不断增大,发生了解组装.以阿霉素(DOX)为模型药物制备了PMgPP-CC/DOX NPs,载药量可达12.5%,对应包封率为83.3%,其粒径与空白PMgPP-CC NPs粒径大小相近,且粒径分布均匀.体外药物释放实验表明,PMgPP-CC/DOX NPs在体液条件下46 h释放了4.47%的DOX,而在10 mmol/L GSH条件下累积释放量达到了50.6%.细胞胞吞实验进一步验证了PMgPP-CC/DOX NPs可高效入胞并在细胞内快速释放DOX.体外细胞毒性(MTT)实验表明,PMgPP-CC/DOX NPs对肝癌HepG-2细胞表现出良好的增殖抑制活性.因此,多功能PMgPP-CC NPs在实现肝靶向纳米精准给药上呈现出良好的应用前景.