Gelation Behavior by the Lanthanoid Adsorption of the Cyanobacterial Extracellular Polysaccharide
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- 作者：Maiko K. Okajima ; Toshimitsu Higashi ; Ryuya Asakawa ; Tetsu Mitsumata ; Daisaku Kaneko ; Tatsuo Kaneko ; Tetsuya Ogawa ; Hiroki Kurata ; Seiji Isoda
- 刊名：Biomacromolecules
- 出版年：2010
- 出版时间：November 8, 2010
- 年：2010
- 卷：11
- 期：11
- 页码：3172-3177
- 全文大小：223K
- 年卷期：v.11,no.11(November 8, 2010)
- ISSN：1526-4602
文摘
The self-organization behavior of an extracellular polysaccharide (sacran) extracted from the cyanobacterium Aphanothece sacrum in response to lanthanoid ion adsorption was investigated. Consequently, cryogenic TEM images revealed that sacran could be cross-linked by Nd3+ trivalent ions and formed a fibrous nanostructural network containing water. Furthermore, sacran adsorbed trivalent metal ions at a 3:1 ratio, which was the theoretical ionic adsorption and showed more efficient adsorption than alginate based on electric conductivity titration. The critical gelation concentrations, Cg, where sacran formed tough gels upon metal ion binding were estimated. The Cg for trivalent metal ions was lower than that for divalent ions, and the Cg for lanthanoid ions was particularly low at 10−3 to 10−4 M, changing every four elemental numbers. The extracellular matrix of Aphanothece sacrum, sacran, may adsorb metal ions to create fibrous nanostructures that reinforce the jelly matrix.