title: Bio-based hydrogels prepared by cross-linking of microbial poly(gamma-glutamic acid) with various saccharides.
abstract: Novel bio-based hydrogels were prepared by cross-linking of microbial poly(gamma-glutamic acid) (PGA) with saccharides such as glucose, maltotriose, and cyclodextrin (CD) in the presence of water-soluble carbodiimide in dimethyl sulfoxide (DMSO) by one-pot synthesis at 25 degrees C for 24 h. The degradation of the gels in alkaline solution (pH 9) at 37 degrees C was also investigated. The PGA gels cross-linked with various neutral saccharides were obtained in relatively high recovery yields by use of a base like 4,4-(dimethylamino)pyridine. The PGA gel cross-linked by glucose showed the highest water absorption of 3000 g/g. The PGA gels cross-linked by CDs showed higher water absorption than those cross-linked by the corresponding linear saccharides. It was revealed that the water absorption of the PGA gel was affected by the cross-linker content and also the structure of cross-linkers as they had an effect on the cross-linking density of the PGA gel. The PGA gels were hydrolyzed under alkaline condition (pH 9) at 37 degrees C. The degradation rate was higher when the cross-linker content of the gel was lower.
authors.affiliation: Kanagawa Industrial Technology Center, 705-1, Shimoimaizumi, Ebina 243-0435, Japan. murakami@kanagawa-iri.go.jp
authors.forename: Saeko
authors.initials: S
authors.lastname: Murakami
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Aoki
mesh_terms: D000042:Absorption; D000468:Alkalies; D002241:Carbohydrates / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D013055:Spectrophotometry, Infrared; D014867:Water
chemical_list: D000468:Alkalies; D002241:Carbohydrates; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D020100:Hydrogels; C511775:poly(gamma-glutamic acid); D014867:Water; D011099:Polyglutamic Acid; D048271:Chitosan