Laboratory of Organic and Macromolecular Chemistry (IOMC) , Friedrich Schiller University Jena , Humboldtstrasse 10 , 07743 Jena , Germany.
Jena Center for Soft Matter (JCSM) , Friedrich Schiller University Jena , Philosophenweg 7 , 07743 Jena , Germany.
Biomacromolecules. 2018 Jul 9;19(7):2759-2771. doi: 10.1021/acs.biomac.8b00362. Epub 2018 Jun 12.
We show the potential of oligo(2-ethyl-2-oxazoline) (Ox)-shielded graft copolymers of (2-aminoethyl)-methacrylate and N-methyl-(2-aminoethyl)-methacrylate for pDNA delivery in HEK cells. For the effect of grafting density and side chain length concerning improved transfection properties through the concept of shielding to be investigated, copolymers were synthesized via the macromonomer method using a combination of cationic ring opening polymerization and reversible addition-fragmentation chain transfer polymerization to vary the degree of grafting (DG = 10 and 30%) as well as the side chain degree of polymerization (DP = 5 and 20). Investigations of the polyplex formation, in vitro flow cytometry, and confocal laser scanning microscopy measurements on the copolymer library revealed classical shielding properties of the Ox side chains, including highly reduced cytotoxicity and a partial decrease in transfection efficiency, as also reported for polyethylene glycol shielding. In terms of the transfection efficiency, the best performing copolymers (A- g-Ox(10) and M- g-Ox(10)) revealed equal or better performances compared to those of the corresponding homopolymers. In particular, the graft copolymers with low DG and side chain DP transfected well with over 10-fold higher IC values. In contrast, a DG of 30% resulted in a loss of transfection efficiency due to missing ability for endosomal release, and a side chain DP of 20 hampered the cellular uptake.
我们展示了寡聚（2-乙基-2-恶唑啉）（Ox）保护的（2-氨基乙基）甲基丙烯酸酯和 N-甲基-（2-氨基乙基）甲基丙烯酸酯接枝共聚物在 HEK 细胞中作为 pDNA 传递的潜力。为了研究接枝密度和侧链长度对通过屏蔽概念改善转染性能的影响，使用阳离子开环聚合和可逆加成-断裂链转移聚合的组合通过大分子单体法合成了共聚物，以改变接枝度（DG=10 和 30%）以及侧链聚合度（DP=5 和 20）。对共聚物库的聚集体形成、体外流式细胞术和共焦激光扫描显微镜测量的研究表明，Ox 侧链具有经典的屏蔽特性，包括高细胞毒性降低和转染效率部分降低，如聚乙二醇屏蔽也有报道。就转染效率而言，表现最好的共聚物（A-g-Ox(10)和 M-g-Ox(10)）与相应的均聚物相比表现出相等或更好的性能。特别是，具有低 DG 和侧链 DP 的接枝共聚物的 IC 值提高了 10 倍以上，转染效果良好。相比之下，由于缺乏内体释放的能力，DG 为 30% 会导致转染效率丧失，而侧链 DP 为 20 则会阻碍细胞摄取。
