PEG接枝氧化石墨烯的制备与细胞成像

通过酯化反应将不同分子量的聚乙二醇(PEG)接枝到氧化石墨烯(GO)表面,得到系列GO-PEG。利用傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)、扫描电子显微镜(SEM)对GO-PEG的结构和形貌进行了表征,用热重分析(TGA)测定了GO-PEG中PEG的接枝量。SEM结果表明GO-PEG的剥离程度高于GO。GO-PEG在磷酸盐缓冲溶液中具有良好的分散稳定性,稳定性与接枝量呈正相关。GO-PEG通过非共价键合作用对荧光素(Flu)的负载量可达1.75 mg·mg-1,且负载量受接枝量影响;另外,GO-PEG对Flu的释放行为具有pH值触发药物释放性能。将接枝PEG的端羟基与Flu共价键合,所得GO-PEG6000-Flu荧光探针实现了对HepG2细胞的成像。

Preparation and Cellular Imaging of PEG Grafted Graphene Oxide

Aseries of functionalized graphene oxide (GO) with biocompatibility were prepared by grafting polyethylene glycol (PEG) with different molecular weights onto the surface of GOvia esterification. Fourier transform infrared (FTIR), Raman spectroscopy and scanning electron microscopy (SEM) were used to investigate structures and morphologies of the as-prepared GO-PEG. Grafting ratios were determined by thermogravimetric analysis (TGA). SEMresults indicate that GO-PEGis better exfoliated than GO. GO-PEGdisplays excellent water dispersity and stability in phosphate buffered saline, and the dispersive stability depends on the grafting ratio. By noncovalent binding interaction, GO-PEGhas high loading capacity (as high as ~1.75 mg·mg^-1) for fluorescein (Flu) depending on the grafting ratio. GO-PEGalso shows pH-triggered release property for Flu. In addition, by covalent binding between terminal hydroxy groups of the grafted PEGchains and Flu, GO-PEG6000-Flu fluorescent probes are prepared and cellular imaging of HepG2 cells is realized by the probes.