光降解自組裝樹枝狀分子在基因傳遞之樹枝狀複合體形成與光觸發DNA釋放

Photodegradable Self-Assembling PAMAM Dendrons for Gene Delivery Involving Dendriplexes Formation and Phototriggered DNA Release

賴鈺森(Yu-Sen Lai)

指導教授 ： 朱智謙

中山醫學大學/健康管理學院/應用化學系碩士班/碩士(2015年)

https://doi.org/10.6834/CSMU.2015.00201

摘要

在基因傳遞的研究中，要成功將所攜帶的核酸分子有效率的釋放，需要合成一個能有效率降解並且能成功釋放核酸的化學結構。本次研究中成功將兩親性分子結構與對光敏感的硝基芐基(o-nitrobenzyl (o-NB))基團結合，得到帶有親疏水端的兩親性光敏感樹枝狀高分子。兩親性樹枝狀高分子結構為親脂性的膽固醇結構與親水性的poly(amido amine) (PAMAM)樹枝狀高分子組成。而結構中親水端的樹枝狀分子在20µM的臨界聚集濃度(CAC)會聚集成核殼狀的微胞。在DNA結合實驗中證明微胞能夠在較低的電荷值與陰離子型的pEGFP-C1利用靜電相互作用形成穩定的複合體，證明對DNA有很好的結合能力。在照光釋放實驗中證明在照射365nm的光可以使結構產生斷裂，並且成功釋放所帶有的DNA。從以上具證明得到一個可經由光控使結構降解，並且能有效率結合DNA與釋放能力的化學結構。

關鍵字

兩親性樹枝狀分子，偽樹枝狀分子，基因轉染，硝基芐基

並列摘要

For effective gene delivery, structural degradation of synthetic carriers is crucial to nucleic acids releasing on the transfection time scale. In this study, we have synthesized the amphiphilic dendritic scaffolds with a photolabile o-nitrobenzyl (o-NB) group that can enable the structural decomposition and controlled release of nucleic acids under active light stimulation. The amphiphilic counterpart composed of a lipophilic cholesterol and hydrophilic poly(amido amine) (PAMAM) dendron allows the self-assembly into a core-shell-like pseudodendrimer above the critical aggregation concentration (CAC) of approximately 20 μM. On the basis of electrostatic interaction, the polycationic pseudodendrimers is capable of forming stable complexes with polyanionic cyclic reporter gene (pEGFP-C1) under low charge excess value, suggesting substantial binding affinity of the dednron assembly toward plasmid DNA. Because the o-NB group in the dendritic structure undergoes efficient photolytic cleavage, in vitro test shows that thus-formed “dendriplexes” are readily
dissociated under 365-nm light irradiation, causing effective dendron degradation accompanied by DNA release. This photochemical strategy provides an opportunity to control over the gene binding and releasing in a spatiotemporal manner.

並列關鍵字

amphiphilic dendrons, pseudodendrimer, nitrobenzyl, gene transfection

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