The use of short peptides conjugated PEI for gene delivery application

• Main Authors: Chiao-chun Yeh, 葉喬淳
• Other Authors: Wei-wen Hu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/06936123999033551920

碩士 === 國立中央大學 === 化學工程與材料工程學系 === 101 === In this study, short peptides were conjugated with polyethyleneimine for the application of gene delivery. By electrostatic interaction, self- assembled nanoparticles using PEI-CPPs, and plasmid DNA were prepared in different amine/phosphate (N/P) ratios. The dynamic laser scattering experiment demonstrated that most of particles formed by peptide modified PEI were between the 200 to 600 nm with positive surfaces, suggesting that these nanoparticles were appropriate for gene transfer. In addition, the modified PEI effectively bound DNA. The MTT assays suggested that modification PEI reduced the cytotoxicity. PEI conjugated either by R9 or SAP10 were unable to transfect cells. In contrast, IL conjugated PEI demonstrated better transfection efficiency than that using sole PEI. We used fluorescein labeling to track plasma DNA delivery. Only PEI-IL can carry DNA to cells. To determine the endosomal escape mechanism of PEI-IL, bafilomycin A1 & chloroquine were applied during transfection. Their results suggested that internalized DNA should be released mainly by proton sponge effect; however, the grafted IL may also perturb endosome membrane and eventually causes membrane disruption. Finally, we used molecular dynamic simulation to elucidate the mechanism of grafted CPP interact with lipid bilyaer. The results indicated that only peptides with hydrophobic domain entering lipid bilayer can stabilize their interactions to cell membrane. In addition, tryptophan in indolicidin plays an important role to the insertion of IL to lipid bilayer.