Department of Polymer Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
Tianjin Key Laboratory of Biomaterial Research, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, 300192, China.
Macromol Biosci. 2021 May;21(5):e2100025. doi: 10.1002/mabi.202100025. Epub 2021 Mar 26.
pH-sensitive polyelectrolytes provide enormous opportunity for siRNA delivery. Especially, their tertiary amine structures can not only bind genes but also act as pH-sensitive hydrophobic structure to control genes release. However, the influence of molecular structures on siRNA delivery still remains elusive, especially for the asymmetric alkyl substituents of the tertiary amine groups. Herein, a library of N-methyl-N-alkyl aminoethyl methacrylate monomers (MsAM) with asymmetric alkyl substituents on the tertiary amine group is synthesized and used to prepare a series of tri-block polycationic copolymers poly(aminoethyl methacrylate)-block-poly (N-methyl-N-alkyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMsMA-PEG). And the properties of these polycations and their self-assembled micelles are characterized, including molecular structure, proton buffering capacity, pH-sensitivity, size, and zeta potential. With the length increase of one alkyl substituent, the proton buffering capacity of both monomers and polycations is demonstrated to be narrowed down. The siRNA delivery efficiency and cytotoxicity of these micelles are also evaluated on HepG2 cells. In particular, poly(aminoethyl methacrylate)-block-poly(N-methyl-N-ethyl aminoethyl methacrylate)-block-poly(ethylene glycol methacrylate) (PAMA-PMEMA-PEG) elicited the best luciferase knockdown efficiency and low cytotoxicity. Besides, PAMA-PMEMA-PEG/siRRM2 also induced significant anti-tumor activity in vitro. These results indicated PAMA-PMEMA-PEG has potential for further use in the design of gene vehicles with the improved efficiency of siRNA delivery.
pH 敏感型聚电解质为 siRNA 递呈提供了巨大的机会。特别是，其叔胺结构不仅可以结合基因，还可以作为 pH 敏感的疏水性结构来控制基因释放。然而，分子结构对 siRNA 递呈的影响仍然难以捉摸，尤其是对于叔胺基团的不对称烷基取代基。在此，合成了一系列具有叔胺基团上不对称烷基取代基的 N-甲基-N-烷基氨基乙基甲基丙烯酸酯单体（MsAM）库，并用于制备一系列三嵌段聚阳离子共聚物聚（氨基乙基甲基丙烯酸酯）-嵌段-聚（N-甲基-N-烷基氨基乙基甲基丙烯酸酯）-嵌段-聚（乙二醇甲基丙烯酸酯）（PAMA-PMsMA-PEG）。并对这些聚阳离子及其自组装胶束的性质进行了表征，包括分子结构、质子缓冲能力、pH 敏感性、粒径和zeta 电位。随着一个烷基取代基的长度增加，两种单体和聚阳离子的质子缓冲能力都显示出变窄的趋势。还在 HepG2 细胞上评估了这些胶束的 siRNA 递呈效率和细胞毒性。特别是，聚（氨基乙基甲基丙烯酸酯）-嵌段-聚（N-甲基-N-乙基氨基乙基甲基丙烯酸酯）-嵌段-聚（乙二醇甲基丙烯酸酯）（PAMA-PMEMA-PEG）引发了最佳的荧光素酶敲低效率和低细胞毒性。此外，PAMA-PMEMA-PEG/siRRM2 还在体外诱导了显著的抗肿瘤活性。这些结果表明，PAMA-PMEMA-PEG 在设计具有提高 siRNA 递呈效率的基因载体方面具有潜力。
