本研究中將非病毒載體—幾丁聚醣以化學改質的方法，進行不同程度的 生物素接枝，並以正負電荷吸引之方式，將生物素幾丁聚醣與質體DNA， 以不同胺基/磷酸根莫耳比組裝成奈米粒子。經由動態雷射散射粒徑分佈儀 顯示，奈米粒子的粒徑大小分佈在66.8 nm 至109.8 nm 以及表面電位介於 21.6 至36.0 mV 之間，均適合應用於基因傳送。此外，經由生物素改質的 幾丁聚醣，依然能提供質體DNA 良好的包覆率與保護能力。同時由LDH 及MTS 測試顯示，生物素改質並不會影響生物合適性，甚至能減緩細胞毒 性。透過生物素與卵白素間作用力的調整，生物素之奈米粒子可以被固定 於基材表面進行基因原位傳送，相較於以懸浮方式送藥的未改質奈米粒 子，本方法可以提升約4.5 倍的轉染效率。 In this research, we modified chitosan, the non-viral vector, with different degrees of biotin moieties. By electrostatic interaction, we prepared self-assemble nanoparticles using biotinylated-chitosan and plasmid DNA in different amine/phosphate ratio. The dynamic laser scattering experiment has demonstrated that particle sizes of biotinylated nanoparticles were between the 66.8 nm to 109.8 nm and the Zeta potential was between 21.6 to 36.0 mV, suggesting that these nanoparticles were suitable for gene delivery. In addition, biotinylated chitosan may effectively bind DNA to protect it from DNase I digestion. The LDH and MTS assays suggested that biotin modification did not only maintain the biocompatibility of chitosan, but also reduce the cytotoxicity. Through the optimatization of biotin-avidin interaction, biotinylated nanoparticles may be immobilized on material surfaces for in situ gene delivery. Compares to bolus gene delivery, our developed in situ gene delivery may enhance the transfection efficiency of 4.5 folds. These results suggest that our strategy successfully improved transfection efficiency of non-viral vectors.
