Conformation of curdlan as observed by tapping mode atomic force microscopy |
| |
Authors: | Yang Jin Hongbin Zhang Yimei Yin Katsuyoshi Nishinari |
| |
Affiliation: | (1) Department of Polymer Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People’s Republic of China;(2) Department of Food & Nutrition, Faculty of Human Life Science, Osaka City University, Sumiyoshi, Osaka 558-5858, Japan |
| |
Abstract: | Tapping mode atomic force microscopy was used to study the bacterial polysaccharide curdlan deposited from dimethyl sulfoxide (Me2SO) and NaOH aqueous solutions. For curdlan in Me2SO, flexible single chains corresponding to a disordered conformation were observed at a concentration of 5 mg/l, and the chain diameter was measured to be 0.65±0.05 nm, which showed good agreement with the expected value of the single polysaccharide chain. Because the concentration of curdlan increased, the chains became more rigid and aggregated, subsequently, the network structures of curdlan appeared. However, curdlan samples deposited from a 5 mM NaOH solution showed entirely different conformations. The chains observed were almost in the form of micelles of several nanometers, which were supermolecular assemblies. The heterogeneously dense zones were observed as the curdlan concentration increased to 40 mg/l. When the concentration of curdlan was above 100 mg/l, which might cause the real concentration of curdlan on the mica substrate after drying treatment exceeding some critical value of gelation, gel network structures were formed. Keeping on increasing the concentration of curdlan, the image showed a more homogeneous fibrous network. |
| |
Keywords: | Curdlan Tapping mode atomic force microscopy Conformation Dimethyl sulfoxide Sodium hydroxide |
本文献已被 SpringerLink 等数据库收录! |
|