Effect of alginate composition and gelling cation on micro-bead swelling.
OBJECTIVE
The purpose of this study was to determine the roles of alginate composition and gelling cations on bead swelling, which affects its durability.


METHODS
Using a 2-channel droplet generator, microspheres were generated with 1.5% solutions of low viscosity high-mannuronic acid (LVM), medium viscosity high-mannuronic acid (MVM), low viscosity high-guluronic acid (LVG) and medium viscosity high-guluronic acid (MVG) alginate. They were gelled by cross-linking with 1.1% solution of either BaCl2 or CaCl2. The diameters of the micro-beads were measured and recorded on day 0. The micro-beads were subsequently washed and incubated in saline at 37 degrees C for 2 weeks with size assessment every 2 days. The data were normalized by calculation of the percentage change from control (day 0) for all groups of micro-beads.


RESULTS
Diameters of all beads were between 550 and 700 microm on day 0. Viscosity had no effect on swelling of Ba++- and Ca++-alginate micro-beads. Ca++-alginate micro-beads were more prone to swelling than the corresponding Ba++-alginate beads. High G-Ba++ beads had only a modest increase in size over time, in contrast to the high M-Ba++.


CONCLUSIONS
Alginate composition and the gelling cation have significant effects on bead swelling.
Darrabie
Marcus D
MD
Department of Surgery, Duke University Medical Center, Durham, NC, USA.
Kendall
William F
WF
Opara
Emmanuel C
EC
D000464:Alginates / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008863:Microspheres; D010316:Particle Size; D014783:Viscosity
D000464:Alginates; D005782:Gels