Microencapsulation of islets and model beads with a thin alginate–ba2+ gel layer using centrifugation
✍ Scribed by Y. G. Park; H. Iwata; Y. Ikada
- Book ID
- 102660100
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 602 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1042-7147
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✦ Synopsis
A microcapsule-type bioartificial pancreas provides a safe, simple technique for implanting immunoisolated islets into various sites. Centrifugal microencapsulation is a promising approach. Various factors must be optimized to increase the efficiency of microencapsulation. In this study, the effects of alginate molecular weights, alginate concentrations, Ba 2 concentrations and centrifugal acceleration on the efficiency of microencapsulation were examined. Sephadex G-50 fine beads were employed as a model of the islets of Langerhans. The efficiency of microencapsulation increased with the increasing concentration and molecular weight of alginate, and with decreasing centrifugal acceleration. It is likely that shearing stress plays a major role in determing the efficiency of microencapsulation. CaCl 2 gave very poor microencapsulation compared with BaCl 2 . The beads' density should be less than 4000 beads/ml to obtain microcapsules containing a single bead when a test-tube of 1.4' cm diameter was used. The thickness of the alginate microcapsule was in the range of 5±20 mm. It was concluded that the improved procedure can effectively enclose large number of islets in microcapsules with a very thin wall without contamination of empty microcapsules.