The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
Biomaterials. 2013 Aug;34(26):6284-98. doi: 10.1016/j.biomaterials.2013.05.006. Epub 2013 May 25.
The interaction of nanocarriers with cells including their transcellular behavior is vital not only for a drug delivery system, but also for the safety of nanomaterials. In an attempt to clarify how the structures of polymers impact the transport mechanisms of their nanocarriers in epithelial cells, three amphiphilic polymers (PEEP-PCL, PEG-PCL and PEG-DSPE) with different hydrophilic or hydrophobic blocks were synthesized or chosen to form different micelle systems here. The endocytosis, exocytosis, intracellular colocalization, paracellular permeability and transcytosis of these micelle systems were compared using Förster resonance energy transfer analysis, real-time confocal images, colocalization assay, transepithelial electrical resistance study, and so on. All micelle systems were found intact during the studies with cells. The endocytosis and exocytosis studies with undifferentiated MDCK cells and the transcytosis study with differentiated MDCK monolayers all indicated the fact that PEG-DSPE micelles achieved the most and fastest transport, followed by PEG-PCL and PEEP-PCL in order. These might be because DSPE has higher hydrophobicity than PCL while PEG has lower hydrophilicity than PEEP. Different in hydrophilic or hydrophobic structures, all kinds of micelles demonstrated similar pathways during endocytosis and exocytosis, both caveolae- and clathrin-mediated but with difference in degree. The colocalization studies revealed different behaviors in intracellular trafficking among the three polymer micelles, suggesting the decisive role of hydrophilic shells on this process. Finally, all micelle systems did not impact the paracellular permeability of test cell monolayer. In conclusion, the hydrophilic and hydrophobic structures of test micelles could influence their transport ability, intracellular trafficking and the transport level under each pathway in MDCK cells.
纳米载体与细胞的相互作用，包括它们的跨细胞行为，不仅对药物传递系统至关重要，而且对纳米材料的安全性也至关重要。为了阐明聚合物的结构如何影响其纳米载体在上皮细胞中的转运机制，我们在这里合成或选择了三种具有不同亲水性或疏水性嵌段的两亲性聚合物（PEEP-PCL、PEG-PCL 和 PEG-DSPE）来形成不同的胶束系统。通过荧光共振能量转移分析、实时共聚焦图像、共定位测定、跨上皮电阻研究等方法比较了这些胶束系统的内吞作用、外排作用、细胞内共定位、细胞旁通透性和转胞吞作用。在与细胞的研究中，所有的胶束系统都被发现是完整的。用未分化的 MDCK 细胞进行的内吞作用和外排作用研究以及用分化的 MDCK 单层进行的转胞吞作用研究都表明，PEG-DSPE 胶束的转运速度最快，其次是 PEG-PCL 和 PEEP-PCL。这可能是因为 DSPE 的疏水性比 PCL 高，而 PEG 的亲水性比 PEEP 低。亲水或疏水结构不同的各种胶束在胞吞作用和胞吐作用过程中表现出相似的途径，都是网格蛋白和小窝蛋白介导的，但程度不同。共定位研究揭示了三种聚合物胶束在细胞内运输中的不同行为，表明亲水壳在这一过程中起着决定性的作用。最后，所有的胶束系统都不会影响测试细胞单层的细胞旁通透性。总之，测试胶束的亲水和疏水结构可以影响它们在 MDCK 细胞中的转运能力、细胞内运输以及每种途径下的转运水平。
