模仿绿色荧光蛋白的荧光聚合物的合成和光学性质研究

受绿色荧光蛋白(GFP)荧光增强原理启发,采用开环聚合制备了两亲性聚乙二醇-生色团-聚己内酯(PEG-c-PCL)嵌段聚合物.通过核磁共振氢谱和碳谱(1H-,13C-NMR)、傅立叶变换红外光谱(FTIR)、凝胶渗透色谱(GPC)和紫外可见吸收光谱(UV-Vis)等证明其结构和性质.生色团和聚合物有相似的紫外吸收光谱,且最大吸收峰都在371 nm.荧光发射光谱表明,生色团的发射峰在427 nm,但聚合物的荧光发射峰出现了6 nm的红移,这是高分子化引起的结果.透射电镜(TEM)和动态光散射(DLS)证明了该两亲性嵌段聚合物能够组装成为纳米粒子.当聚合物组装成纳米粒子后,荧光强度增大了55倍,并且荧光发射峰出现了14 nm的红移,这些现象可归结于荧光生色团自由旋转的限制和组装导致的相互作用增强.

SYNTHESIS AND OPTICAL PROPERTIES OF GFP-MIMIC FLUORESCENT POLYMER

To mimic the fluorescence enhancement behavior of green fluorescent protein(GFP),an amphiphilic polymer,poly(ethylene glycol)-chromophore-poly(ε-caprolactone)(PEG-c-PCL),was successfully prepared by ring-opening polymerization using chromophore-endcapped PEG as the macroinitiator.1H-and 13C nuclear magnetic resonance(1H and 13C-NMR),Fourier transform infrared spectroscopy(FTIR),gel permeation chromatography(GPC) and ultraviolet-visible absorption(UV-Vis) were applied to study the structure and properties of PEG-c-PCL.Both the chromophore and PEG-c-PCL gave similar UV-Vis spectra with a maximum absorption peak at about 371 nm.From the emission spectra,the chromophore had an emission peak at about 427 nm,while PEG-c-PCL showed a 6 nm red-shift,attributable to the influence of polymerization.The amphiphilic PEG-c-PCL could self-assemble into nanoparticles with a diameter of about 160 nm,which was confirmed by transmission electron microscopy(TEM) and dynamic light scattering(DLS) measurements.Importantly,the emission intensity of PEG-c-PCL increased by about 55 times after self-assembly into nanoparticles,and the emission peak showed a 14 nm red-shift in the emission spectrum.These phenomena could be attributed to the chromophore's rotation restriction and the increased interactions after self-assembly.Finally,the self-assembled PEG-c-PCL nanoparticles were successfully used in cell imaging,illustrating the potential application of this new kind of fluorescent polymer.