羧甲基茯苓多糖结构的红外光谱表征与原子力显微镜观测

Characterization of Structure of Carboxymethylpachymaran by IR Spectrum and Atomic Force Microscopy

用傅里叶变换红外光谱对羧甲基茯苓多糖(carboxymethylpachymaran,CMP)的结构进行了表征,用原子力显微镜(atomic force microscopy,AFM)对不同溶液环境下CMP的形态变化进行了观测。结果表明:经过羧甲基修饰,茯苓多糖在水中的溶解性显著增加,890 cm-1处的-βD-葡聚糖特征吸收峰明显减弱,1 333 cm-1处出现次甲基振动吸收峰,1 606 cm-1处出现C O非对称伸缩振动吸收峰,表明羧甲基化成功;原子力显微镜分析表明:在不同溶液条件下,CMP分子以不同形态存在,多糖溶液的浓度、离子强度及溶剂的物化特性均能对CMP的分子链构象及链间相互作用形式产生影响,推测可能与CMP分子内、分子间的氢键缔合及静电作用有关,CMP分子与云母基底间的吸附及静电作用也会对CMP的分子链构象及图像质量产生影响。

The structure of Carboxymethylpachymaran was characterized using Fourier transform infrared spectroscopy.Morphological changes of carboxymethylpachymaran （CMP） were observed under different solution conditions by atomic force microscopy（AFM）.After the carboxymethylation,the solubility of pachyman in the water was significantly increased,its β-D-glucan characteristic absorption peak at 890 cm-1 became weak obviously,and its methylene vibration absorption peak and CO antisymmetrical stretch vibration absorption peak appeared at 1 333 and 1 606 cm-1 respectively,which indicated that the carboxymethylation succeeded.The analysis of AFM results showed that CMP molecules existed in different morphology under different solution conditions,and that the concentration,ionic strength and solvent physical chemistry characteristics of polysaccharide solution had effects on the CMP chains conformation and the action mode between different molecular chains.The phenomena were considered to be related to hydrogen bond association and intramolecular and intermolecular electrostatic interactions of CMP.Meanwhile,the affinity and electrostatic interaction between CMP molecules and the mica substrate also had an influence on the CMP chains conformation and the image quality.