title: Genipin cross-linked alginate-chitosan microcapsules: membrane characterization and optimization of cross-linking reaction.
abstract: The genipin cross-linked alginate-chitosan (GCAC) microcapsule, composed of an alginate core and a genipin cross-linked chitosan membrane, was recently proposed for live cell encapsulation and other delivery applications. This article for the first time describes the details of the microcapsule membrane characterization using a noninvasive and in situ method without any physical or chemical modifications on the samples. Results showed that the cross-linking reaction generated the fluorescent chitosan-genipin conjugates. The cross-linked chitosan membrane was clearly visualized by confocal laser scanning microscopy (CLSM). A straightforward assessment on the membrane thickness and relative intensity was successfully achieved. CLSM studies showed that the shell-like cross-linked chitosan membranes of approximately 37 microm in thickness were formed surrounding the microcapsule. The reaction variables, including cross-linking temperature and time significantly affected the fluorescence intensity of the membranes. Elevating the cross-linking temperature from 4 to 37 degrees C drastically intensified the membrane fluorescence, suggesting the attainment of a high degree of cross-linking on the chitosan membrane. Extended cross-linking time altered the cross-linked membranes in modulation. Although genipin concentration and cross-linking time had little effects on the membrane thickness, cross-linking at higher temperatures tended to form relatively thinner membranes.
authors.affiliation: Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, 3775 University Street, Montreal, Quebec, H3A 2B4, Canada.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Ouyang
authors.forename: Bisi
authors.initials: B
authors.lastname: Lawuyi
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry; D002236:Carbohydrate Conformation; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D057889:Iridoid Glycosides; D039823:Iridoids; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D011714:Pyrans / Q000737:chemistry*
chemical_list: D000464:Alginates; D002214:Capsules; D003432:Cross-Linking Reagents; D006603:Hexuronic Acids; D057889:Iridoid Glycosides; D039823:Iridoids; D011714:Pyrans; D020723:Glucuronic Acid; D048271:Chitosan; C007834:genipin