基于硝基苯类光扳机两亲性嵌段共聚物的合成及其光响应性质研究

The Synthesis of the Amphiphilic Block Copolymer Based on o-Nitrobenzyl Phototrigger and the Research of Photo-responsive Properties

以香草醛为原料,制备了连接十二烷基长链的硝基苯类光扳机S-(o-硝基-m-甲氧基-p-十二烷氧基苄醇)(VND),并通过酰胺化反应与PEG1000-NH2生成具有光响应性的两亲性嵌段共聚物聚乙二醇-S-(o-硝基-m-甲氧基-p-十二烷氧基苄酯)(PEG-VND)。红外光谱(FT-IR)、核磁共振(1 HNMR)证明了合成的结构即为目标产物。PEG-VND可以在水中自组装成胶束,通过马尔文粒径仪和透射电镜(TEM)测定胶束的粒径。用紫外-可见光谱法(UV-Vis)研究胶束溶液随光照时间推移吸收光谱的变化。包载模型药物尼罗红后,检测PEG-VND对尼罗红的光控释放性质,结果表明:PEG-VND随光照时间的增加逐渐降解,尼罗红荧光发射强度逐渐减小,说明光照使得胶束解组装,释放模型药物。制备的快速光响应型控制释药聚合物胶束,具有潜在的生物医学应用的可能性。

A photo-responsive amphiphilic block copolymer-Polyethylene glycol-S-（ o-nitro-m-methoxy-p- dodecone alkoxy benzyl ester） （PEG-VND） was for the first time designed, and synthesized based on o- Nitrobenzyl phototrigger （VND） and polymer PEGI000-NH2. And the related phototrigger S-（o-nitro-m- methoxy-p-dodecone alkoxy benzyl alcohol） （VND） was synthesized from vanilin and 1-bromododecane as raw materials. The molecular structure was characterized by infrared spectroscope（FT-IR） and nuclear magnetic resonance（1 HNMR）. Their physical properties, self-assembly, and model drug release of PEG-VND were thoroughly investigated. The sizes and images of PEG-VND micelles were determined by malvern Zetasizer Nano ZS and transmission electron microscopy （TEM）. The characteristic absorption spectrums of these copolymers changed along with the UV irradiation and then leveled off, indicating that the o-nitrobenzyl groups were gradually photocleaved from copolymers until the completion of photocleavage. The PEG-VND copolymers self assembled into micelles in aqueous solution. Model drug nile red can be loaded inside the micelles and can be released in a controlled manner by changing the irradiation time, which was induced by gradually photocleaving the PEG-VND. This work provides a facile strategy not only for the photoresponsive o-nitrobenzyl-based block copolymers but also for the fabrication of photoresponsive nanomedicine potential.