Liechty William B, Scheuerle Rebekah L, Vela Ramirez Julia E, Peppas Nicholas A
McKetta Dept. of Chemical Engineering The University of Texas at Austin Austin TX 78712.
Dept. of Biomedical Engineering The University of Texas at Austin Austin TX 78712.
Bioeng Transl Med. 2018 Nov 22;4(1):17-29. doi: 10.1002/btm2.10120. eCollection 2019 Jan.
The design of intracellular drug delivery vehicles demands an in-depth understanding of their internalization and function upon entering the cell to tailor the physicochemical characteristics of these platforms and achieve efficacious treatments. Polymeric cationic systems have been broadly accepted to be membrane disruptive thus being beneficial for drug delivery inside the cell. However, if excessive destabilization takes place, it can lead to adverse effects. One of the strategies used to modulate the cationic charge is the incorporation of hydrophobic moieties, thus increasing the hydrophobic content. We have demonstrated the successful synthesis of nanogels based on diethylaminoethyl methacrylate and poly(ethylene glycol) methyl ether methacrylate. Addition of the hydrophobic monomers -butyl methacrylate or 2-(-butylamino)ethyl methacrylate shows improved polymer hydrophobicity and modulation of the critical swelling pH. Here, we evaluate the cytocompatibility, uptake, and function of these membrane-destabilizing cationic methacrylated nanogels using in vitro models. The obtained results suggest that the incorporation of hydrophobic monomers decreases the cytotoxicity of the nanogels to epithelial colorectal adenocarcinoma cells. Furthermore, analysis of the internalization pathways of these vehicles using inhibitors and imaging flow cytometry showed a significant decrease in uptake when macropinocytosis/phagocytosis inhibitors were present. The membrane-disruptive abilities of the cationic polymeric nanogels were confirmed using three different models. They demonstrated to cause hemolysis in sheep erythrocytes, lactate dehydrogenase leakage from a model cell line, and disrupt giant unilamellar vesicles. These findings provide new insights of the potential of polymeric nanoformulations for intracellular delivery.
细胞内药物递送载体的设计需要深入了解其进入细胞后的内化过程和功能，以便调整这些平台的物理化学特性并实现有效的治疗。聚合物阳离子系统已被广泛认为具有膜破坏作用，因此有利于细胞内的药物递送。然而，如果发生过度的膜破坏，可能会导致不良反应。用于调节阳离子电荷的策略之一是引入疏水基团，从而增加疏水性。我们已经证明了基于甲基丙烯酸二乙氨基乙酯和聚（乙二醇）甲基醚甲基丙烯酸酯成功合成了纳米凝胶。添加疏水单体——甲基丙烯酸丁酯或甲基丙烯酸2-（叔丁氨基）乙酯显示出聚合物疏水性的改善以及临界溶胀pH的调节。在此，我们使用体外模型评估这些具有膜破坏作用的阳离子甲基丙烯酸化纳米凝胶的细胞相容性、摄取和功能。所得结果表明，疏水单体的引入降低了纳米凝胶对上皮性结直肠腺癌细胞的细胞毒性。此外，使用抑制剂和成像流式细胞术分析这些载体的内化途径表明，当存在巨胞饮作用/吞噬作用抑制剂时，摄取量显著降低。使用三种不同模型证实了阳离子聚合物纳米凝胶的膜破坏能力。它们在绵羊红细胞中引起溶血，从模型细胞系中泄漏乳酸脱氢酶，并破坏巨型单层囊泡。这些发现为聚合物纳米制剂用于细胞内递送的潜力提供了新的见解。
