【摘要】 运用原子力显微镜(Atomic Force Microscopy,AFM)技术对丹皮多糖的形貌结构进行研究。采用多糖水溶液液珠滴降法制样,AFM非接触模式(non-contact mode)扫描。AFM图像显示,丹皮多糖分子呈现近似球形的结构形貌,小球形颗粒直径为50 nm~80 nm左右,推测是丹皮多糖的基本结构单位。在一定浓度和条件下,丹皮多糖分子小球形颗粒可发生聚集,其中以直径约170 nm~220 nm的圈状和中空球聚集体结构较有代表性。将多糖稀溶液80℃加热,可促进多糖分子发生自组装,缔合形成长链超分子结构。超分子结构中的每一亚单位亦由小球形颗粒聚集紧缩而成。AFM图像研究表明丹皮多糖分子在水溶液中倾向采取球状或线团构象并通过链间氢键作用形成分子缔合组装。更多还原

【Abstract】 A complex polysaccharide PSM2b-A,extracted from root cortex of Paeonia suffruticosa,was examined by atomic force microscopy.Samples were drop deposited from aqueous solution onto freshly cleaved mica,air dried,and imaged in air using non-contact mode.The images of PSM2b-A had revealed predominantly globular structure with a size from 50 nm to 80 nm in diameter.PSM2b-A also exhibited a circle or hollow sphere structure that was believed to be the associative aggregates of globular particles as evidenced by the 3D images.Measurements showed that circles or hollow spheres had a size about 170 nm~220 nm in external diameter.Interestingly,after incubating diluted solution of PSM2b-A at 80 ℃,the molecules were shown to display an extended entangled chain composed of bead-like subunit as visualized in high magnification.Each bead-like subunit was supposed to be condensed state of circles or hollow spheres due to intra-and/or intermolecular interactions.AFM research suggest that PSM2B-A is likely to assume a coiled conformation and easily self-assembly through hydrogen bond intermolecularly.更多还原