title: Effect of prolonged gelling time on the intrinsic properties of barium alginate microcapsules and its biocompatibility.
abstract: Pericapsular fibrotic overgrowth (PFO) may be attributed to an immune response against microcapsules themselves or to antigen shedding through microcapsule pores from encapsulated islet tissue. Modification of microcapsules aimed at reducing pore size should prevent PFO and improve graft survival. This study investigated the effect of increased gelling time (20 vs. 2 min) in barium chloride on intrinsic properties of alginate microcapsules and tested their biocompatibility in vivo. Prolonged gelling time affected neither permeability nor size of the microcapsules. However, prolonged gelling time for 20 min produced brittle microcapsules compared to 2 min during compression test. Encapsulation of human islets in both types of microcapsules affected neither islet viability nor function. The presence of PFO when transplanted into a large animal model such as baboon and its absence in small animal models such as rodents suggest that the host immune response towards alginate microcapsules is species rather than alginate specific.
authors.affiliation: Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia.
authors.forename: Vijayaganapathy
authors.initials: V
authors.lastname: Vaithilingam
authors.forename: Gabriella
authors.initials: G
authors.lastname: Kollarikova
authors.forename: Meirigeng
authors.initials: M
authors.lastname: Qi
authors.forename: Igor
authors.initials: I
authors.lastname: Lacik
authors.forename: Jose
authors.initials: J
authors.lastname: Oberholzer
authors.forename: Gilles J
authors.initials: GJ
authors.lastname: Guillemin
authors.forename: Bernard E
authors.initials: BE
authors.lastname: Tuch
mesh_terms: D000464:Alginates / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism*; D002214:Capsules; D002470:Cell Survival; D018914:Cells, Immobilized / Q000166:cytology; D005260:Female; D005782:Gels / Q000737:chemistry / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology; D016381:Islets of Langerhans Transplantation; D008297:Male; D008422:Materials Testing; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D010215:Papio; D010539:Permeability; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D002214:Capsules; D005782:Gels; D006603:Hexuronic Acids; D020723:Glucuronic Acid