title: Photoshrinkage in polysaccharide gels with trivalent metal ions.
abstract: The giant anionic polysaccharide "sacran", which is composed of 6-deoxyhexoses, pentoses, uronic acids as well as hexoses, showed hydrophobization and insolubilization phenomena in response to ultraviolet light irradiation. The sacran solution became turbid, and microparticles were formed by photoirradiation. To visualize the results of this photoreaction, anionic polysaccharide gels cross-linked by metal cations were used. As a result, we observed that sacran-gels with trivalent metal ions gradually contracted depending on the photoirradiation energy. In contrast, alginate gels used as a comparison degraded instead of contracting. This photoshrinkage of the sacran gels may be attributed to the hydrophobization of uronic acid based on photodecarboxylation. We propose that sacran-metal ion gels can function as effective, photoresponsive gels.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
authors.forename: Maiko K
authors.initials: MK
authors.lastname: Okajima
authors.forename: Quyen Thi
authors.initials: QT
authors.lastname: le Nguyen
authors.forename: Seiji
authors.initials: S
authors.lastname: Tateyama
authors.forename: Hideaki
authors.initials: H
authors.lastname: Masuyama
authors.forename: Takumi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Tetsu
authors.initials: T
authors.lastname: Mitsumata
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kaneko
mesh_terms: D000464:Alginates / Q000737:chemistry; D003653:Decarboxylation; D005782:Gels / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006601:Hexoses / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008970:Molecular Weight; D010316:Particle Size; D010429:Pentoses / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014466:Ultraviolet Rays; D014574:Uronic Acids / Q000737:chemistry
chemical_list: D000464:Alginates; D005782:Gels; D006601:Hexoses; D006603:Hexuronic Acids; D007477:Ions; D008670:Metals; D010429:Pentoses; D011134:Polysaccharides; D014574:Uronic Acids; C571099:sacran; D020723:Glucuronic Acid