College of Pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China; Department of Polymer Science and Technology, Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
College of Pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China.
Colloids Surf B Biointerfaces. 2022 Jan;209(Pt 2):112178. doi: 10.1016/j.colsurfb.2021.112178. Epub 2021 Oct 26.
Optimal combination of hydrophobic-hydrophilic balance, proton buffering and electrostatic interaction is the key issue for designing polycations as efficient gene vectors and antibacterial agents. Herein, we screened a series of pH-sensitive quaternary ammonium-based amphiphilic triblock copolymers, mPEG-P(DPA/DMA)-PQA (TDDE-x), which had different pKa values and proton buffering capacities. Significantly, we found that both the highest siRNA intracellular delivery efficiency and the strongest antibacterial capacity occurred on TDDE-3 micelles with the segment structure of mPEG-P(DPA/DMA)-PQA. The TDDE-3/siRNA complex achieved 67% silencing efficiency on H9C2 cells (N/P = 5, 50 nM siRNA), higher than the advanced commercial transfection reagents RNAiMAX (58%) and Lipo2000 (30%). Moreover, TDDE-3 micelles showed quite low MICs of 32 μg/mL and 8 μg/mL against E. coli and S. aureus, respectively. Further studies on the structure-function relationship indicated that TDDE-3 micelles could mediate robust endosome escape and siRNA cytosolic release, and strong bacterial cell membrane-destabilizing function. Undoubtedly, this work reveals the possibility for double optimization of siRNA intracellular delivery efficiency and antibacterial activity of amphiphilic polycations by reasonable structure design, which is significant for low-cost development and clinical translation of efficient multifunctional polycations.
疏水性-亲水性平衡、质子缓冲和静电相互作用的最佳组合是设计高效基因载体和抗菌剂的聚阳离子的关键问题。在此，我们筛选了一系列具有不同 pKa 值和质子缓冲能力的 pH 敏感的季铵盐两亲性三嵌段共聚物 mPEG-P(DPA/DMA)-PQA（TDDE-x）。值得注意的是，我们发现，在具有 mPEG-P(DPA/DMA)-PQA 段结构的 TDDE-3 胶束上，siRNA 的细胞内转染效率最高，同时抗菌能力最强。TDDE-3/siRNA 复合物在 H9C2 细胞（N/P = 5，50 nM siRNA）上达到 67%的沉默效率，高于先进的商业转染试剂 RNAiMAX（58%）和 Lipo2000（30%）。此外，TDDE-3 胶束对大肠杆菌和金黄色葡萄球菌的 MIC 分别低至 32 μg/mL 和 8 μg/mL。进一步的结构-功能关系研究表明，TDDE-3 胶束可以介导强大的内涵体逃逸和 siRNA 细胞质释放，以及强大的细菌细胞膜破坏功能。毫无疑问，这项工作通过合理的结构设计揭示了双重优化两亲性聚阳离子的 siRNA 细胞内转染效率和抗菌活性的可能性，这对于高效多功能聚阳离子的低成本开发和临床转化具有重要意义。
