Document Detail


Microcapsules made by enzymatically tailored alginate.
MedLine Citation:
PMID:  12579569     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Alginate is widely used for encapsulation of cells. Alginate is a linear block copolymer consisting of mannuronic acid (M) and guluronic acid (G). It has been shown that enzymes known as C-5 epimerases convert M to G in the polymer chain, giving rise to novel alginates with tailored properties. One of these enzymes, AlgE4, converts M blocks into blocks of strictly alternating M and G. In this study we investigated how alginate epimerized by AlgE4 affected capsule properties such as stability and permeability. Inhomogeneous calcium-alginate gel beads were made with original and AlgE4-epimerized alginates of different origin. The epimerized alginates formed initially smaller alginate gels that showed increased resistance to osmotic swelling compared with the original nonmodified alginate samples. The permeability, measured as diffusion of immunoglobulin (Ig) G into Ca/Ba-alginate gel beads, was reduced by epimerization and further reduced by addition of poly-L-lysine (PLL). The osmotic stability of alginate-poly-D-lysine(PDL)-alginate capsules was enhanced by the use of epimerized alginate; indeed, stable capsules with low permeability to tumor necrosis factor (TNF) could be made with low PDL exposures. Finally, alginate with an alternating structure interacted more strongly with the alginate-PLL capsule than did alginate with a high content of M blocks or G blocks or than an alginate consisting mainly of M.
Authors:
Berit L Strand; Yrr A Mørch; Kjersti R Syvertsen; Terje Espevik; Gudmund Skjåk-Braek
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomedical materials research. Part A     Volume:  64     ISSN:  1549-3296     ISO Abbreviation:  -     Publication Date:  2003 Mar 
Date Detail:
Created Date:  2003-02-11     Completed Date:  2003-12-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101234237     Medline TA:  J Biomed Mater Res A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  540-50     Citation Subset:  IM    
Copyright Information:
Copyright 2003 Wiley Periodicals, Inc.
Affiliation:
Department of Biotechnology, Sem Saelandsvei 6/8, 7491 Trondheim, Norway. Berit.Loeken.Strand@chembio.ntnu.no
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MeSH Terms
Descriptor/Qualifier:
Alginates / chemistry*,  metabolism
Animals
Calcium / chemistry
Carbohydrate Sequence
Drug Compounding*
Humans
Immunoglobulin G / metabolism
Iodine Radioisotopes / metabolism
Mice
Molecular Structure
Particle Size
Polylysine / analogs & derivatives*,  chemistry,  metabolism
Racemases and Epimerases / metabolism*
Tumor Necrosis Factor-alpha / metabolism
Chemical
Reg. No./Substance:
0/Alginates; 0/Immunoglobulin G; 0/Iodine Radioisotopes; 0/Tumor Necrosis Factor-alpha; 0/alginate-polylysine-alginate; 25104-18-1/Polylysine; 7440-70-2/Calcium; EC 5.1.-/Racemases and Epimerases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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