两亲嵌段共聚物的合成及纳米自组装

Synthesis and Self-Assembly of Amphiphilic Triblock Copolymers

首先用苄氧羰基赖氨酸和三光气反应合成苄氧羰基赖氨酸酸酐,然后将聚乙二醇中活性较弱的羟基转化为氨基,最后以双端氨基聚乙二醇作为引发剂,采用阴离子开环聚合合成了聚(Nε-苄氧羰基赖氨酸)-聚乙二醇-聚(Nε-苄氧羰基赖氨酸)(PLL(Z)-PEG-PLL(Z))。PLL(Z)-PEG-PLL(Z)经去保护后得到带正电荷的聚赖氨酸-聚乙二醇-聚赖氨酸(PLL-PEG-PLL)。PLL(Z)-PEG-PLL(Z)在水溶液中自组装形成的聚集体类似于纳米多孔聚集体结构,具有疏松的空洞,原子力显微镜观测其呈球形,其大小为220 nm左右。

A novel amphiphilic triblock copolymers which consist of poly（ethylene glycol） （PEG） and poly（ε- （benzyloxycarbonyl）-Lysine PLL（Z） were synthesized by anion ring opening polymerization of N-carboxyanhydride of N^t- （benzyloxycarbonyl）-L- Lysine （Lys（Z）-NCA） using α-amino-ω-amino-poly（ ethylene glycol） as the initiator in dimethylformamide（DMF）. Then, poly （L-Lysine）-poly （ethylene glycol） -poly （L-Lysine） （PLL-PEG-PLL） was obtained by removing the protecting groups. The blocks were characterized by infrared spectroscopic （IR）, hydrogen nuclear magnetic resonance spectrum （^1H-NMR）. The results show that the block copolymers are of well defined structure The self-assembled behaviors of PLL （Z）-PEG-PLL （Z） in aqueous medium were investigated and aggregates morphology of triblock copolymer were observed by atom force microscopy. The results show that PLL （Z）-PEG-PLL（Z） forms hollow sphere aggregates with an average diameter at 220 nm. This regular nanometer structure has potential applications in biomedicine.