Ministry of Education Engineering Research Center of Starch & Protein Processing, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China.
CAS Lamvac Biotech Co., Ltd., No.3, Lanyue Road, Guangzhou Science Park, Guangzhou Hi-Tech Industrial Development Zone, Guangzhou, Guangdong, 510663, China.
Sci Rep. 2017 Nov 1;7(1):14844. doi: 10.1038/s41598-017-14551-1.
This study aims at developing biocompatible starch based gene carriers with good gene delivery and transfection efficacy. By controlling the molecular weight and aggregation behavior of spermine modified cationic starch (CS) molecules, nanocomplexes spontaneously formed through electrostatic interaction using CS and plasmid pAcGFP1-C1 (pDNA) displaying different structural changes (particle size, zeta potential, shape, compactness) response to the simulated intracellular pH variation. Results indicated that CS2 with weight average molecular weight (Mw) of 6.337 × 10 g/mol displayed relatively higher transfection efficacy (~30%) in HepG2 cells than others and revealed significantly low cytotoxicity. By simulating the intracellular pH variation, Dynamic Light Scattering (DLS) and Small Angle X-ray Scattering (SAXS) results demonstrated that CS2 could bind to pDNA tightly and form nanocomplexes with smaller and compact internal aggregate structure at acidic conditions, which facilitated the effective pDNA protection under endosome pH change, while larger and loose internal aggregate structure at physiological pH which promoted the disintegration of CS2/pDNA nanocomplexes. Therefore, CS with suitable Mw of around 6.0 × 10 g/mol represents a potential gene carrier for gene delivery. This study also demonstrated that controlling the internal nanostructure change of polymer/gene nanocomplexes could provide guidance in designing effective starch based gene carriers.
本研究旨在开发具有良好基因传递和转染效果的生物相容性淀粉基基因载体。通过控制精胺改性阳离子淀粉（CS）分子的分子量和聚集行为，CS 与质粒 pAcGFP1-C1（pDNA）通过静电相互作用自发形成纳米复合物，对模拟细胞内 pH 值变化表现出不同的结构变化（粒径、Zeta 电位、形态、紧凑度）。结果表明，重均分子量（Mw）为 6.337×10 g/mol 的 CS2 在 HepG2 细胞中的转染效率（~30%）相对较高，且细胞毒性较低。通过模拟细胞内 pH 值变化，动态光散射（DLS）和小角 X 射线散射（SAXS）结果表明，CS2 可以在酸性条件下与 pDNA 紧密结合，并形成具有较小和紧凑内部聚集结构的纳米复合物，从而在内涵体 pH 值变化下有效保护 pDNA，而在生理 pH 值下则形成较大和松散的内部聚集结构，促进 CS2/pDNA 纳米复合物的解体。因此，Mw 约为 6.0×10 g/mol 的 CS 代表了一种有潜力的基因传递载体。本研究还表明，控制聚合物/基因纳米复合物的内部纳米结构变化可以为设计有效的淀粉基基因载体提供指导。
