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利用小肠上皮细胞顶膜侧和基底侧pH的差异以及新生儿Fc受体(neonatal Fc receptor,FcRn)与其配体结合的pH依赖特性可能增加配体修饰的纳米载体从小肠上皮细胞顶膜侧向基底侧的转运,从而促进药物的吸收。本课题制备了靶向于FcRn的短肽FcBP(IgG Fc段结合肽,IgG Fc domain-binding peptides)修饰的聚乙二醇-聚ε-己内酯[poly(ethyl ethylene phosphate)-co-poly(ε-caprolactone),PEG-PCL]胶束并在人克隆结肠腺癌细胞(human colon adenanocaricinoma cell lines,Caco-2)上考察了pH和靶头密度对胶束摄取与外排过程的影响。采用薄膜水化法制备不同靶头修饰密度的包载香豆素6(coumarin 6,C6)的PEG-PCL主动胶束和被动胶束,并用激光粒度测定仪测定其粒径,透射电镜观察其形态,流式细胞术测定各主、被动胶束在不同pH值下的摄取和外排以及FcRn在胶束摄取中的作用。结果表明,PEG-PCL胶束的粒径约为30 nm,FcBP的修饰不影响胶束的粒径。pH和靶头密度都对FcBP修饰的PEG-PCL胶束的摄取有影响。主动胶束在pH 6.0的摄取量显著高于在pH7.4的摄取量,并且在两种pH下主动胶束的摄取量都表现出随靶头密度的增大先增大后减少的趋势。进一步研究胶束的外排表明,胶束在pH 6.0下摄取后可以在pH 7.4环境中外排,外排量与靶头密度有关,其中靶头密度10%的主动胶束外排量最大,显示出较强的跨膜转运递送的潜力。同时,竞争性抑制实验验证了胶束的摄取与配体和受体的作用有关。本研究为应用FcBP修饰的PEG-PCL胶束进行跨膜转运药物打下一定的基础,为纳米载体的设计提供了一定的参考。
Utilizing the difference in pH between the apical and basolateral sides of the small intestine epithelium and the pH-dependent binding of the neonatal Fc receptor (FcRn) to its ligands may increase the potential of the ligand-modified nanocarriers to migrate laterally from the apical membrane of the small intestinal epithelium Substrate side of the transport, thereby promoting the absorption of drugs. In this study, poly (ethyl ethylene phosphate) -co-poly (poly-ethylene-co-polyglycolide) modified with FcRn short peptide FcBP (IgG Fc domain-binding peptides) (ε-caprolactone, PEG-PCL) micelles and the effects of pH and target density on micellar uptake and efflux were investigated on human colon adenocarcinoma cell lines (Caco-2). The PEG-PCL active micelles and passive micelles containing coumarin 6 (C6) were prepared by thin-film hydration method and their particle sizes were measured by laser particle size analyzer. Transmission electron microscopy Morphology and flow cytometry were used to determine the uptake and efflux of main and passive micelles at different pH values and the role of FcRn in micellar uptake. The results showed that the size of PEG-PCL micelles was about 30 nm, and the modification of FcBP did not affect the size of micelles. Both pH and target density have an effect on uptake of FcBP-modified PEG-PCL micelles. The uptake of active micelles at pH 6.0 was significantly higher than at pH 7.4, and the uptake of active micelles at both pHs showed a tendency to increase first and then decrease with increasing target density. Further study of the efflux of the micelles indicates that the micelles can be effluxed at a pH of 7.4 after exposure at pH 6.0. The efflux volume is related to the target density, with the largest amount of active micelles exiting at a target density of 10% The potential for greater transmembrane transport delivery. In the meantime, competitive inhibition experiments demonstrated that the uptake of micelles is related to the roles of ligands and receptors. This study laid a solid foundation for the transmembrane transport of Fc-modified PEG-PCL micelles and provided some references for the design of nanocarriers.