The main cause of alginate polycation capsule breakage under physiological
conditions is probably the osmotic swelling of the alginate core
owing to the Donnan equilibrium set up by the negative charges of
the carboxyl groups not involved in cooperative binding of counterions
in the junction zones of the network. In the present paper we show
how capsules can be stabilized extensively by reducing their swelling
capacity in various ways. Alginate polycation capsules with good
chemical and mechanical stability have been made by controlling their
swelling behaviour through selection of capsule material according
to chemical structure and molecular weight, as well as by controlling
the kinetics of the capsule formation. Stable capsules have been
made either by increasing the strength of the polyanion-polycation
membrane, or by keeping a low-swelling gel network in the core. The
latter capsules are made from an alginate rich in guluronic acid
both in the core and in an outer coating, and with anisotropic distribution
of the polymer material in the core where the concentration at the
surface is higher than that in the centre of the capsule. Some functional
properties of these capsules, such as porosity, have also been studied.
(C) 1996 Elsevier Science Limited
%0 Journal Article
%1 Thu1996a
%A Thu, B.
%A Bruheim, P.
%A Espevik, T.
%A Smidsrod, O.
%A SoonShiong, P.
%A Skjak-Braek, G.
%C THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5
1GB
%D 1996
%I ELSEVIER SCI LTD
%J Biomaterials
%K ; ;; [ISI:] acid alginate; beads; cytokine functional gel immobilization insulin insulin; islets; material; microcapsules; microencapsulation; production; properties; release; swelling; transplantation
%N 11
%P 1069 -- 1079
%T Alginate polycation microcapsules .2. Some functional properties
%V 17
%X The main cause of alginate polycation capsule breakage under physiological
conditions is probably the osmotic swelling of the alginate core
owing to the Donnan equilibrium set up by the negative charges of
the carboxyl groups not involved in cooperative binding of counterions
in the junction zones of the network. In the present paper we show
how capsules can be stabilized extensively by reducing their swelling
capacity in various ways. Alginate polycation capsules with good
chemical and mechanical stability have been made by controlling their
swelling behaviour through selection of capsule material according
to chemical structure and molecular weight, as well as by controlling
the kinetics of the capsule formation. Stable capsules have been
made either by increasing the strength of the polyanion-polycation
membrane, or by keeping a low-swelling gel network in the core. The
latter capsules are made from an alginate rich in guluronic acid
both in the core and in an outer coating, and with anisotropic distribution
of the polymer material in the core where the concentration at the
surface is higher than that in the centre of the capsule. Some functional
properties of these capsules, such as porosity, have also been studied.
(C) 1996 Elsevier Science Limited
@article{Thu1996a,
__markedentry = {[phpts:6]},
abstract = {The main cause of alginate polycation capsule breakage under physiological
conditions is probably the osmotic swelling of the alginate core
owing to the Donnan equilibrium set up by the negative charges of
the carboxyl groups not involved in cooperative binding of counterions
in the junction zones of the network. In the present paper we show
how capsules can be stabilized extensively by reducing their swelling
capacity in various ways. Alginate polycation capsules with good
chemical and mechanical stability have been made by controlling their
swelling behaviour through selection of capsule material according
to chemical structure and molecular weight, as well as by controlling
the kinetics of the capsule formation. Stable capsules have been
made either by increasing the strength of the polyanion-polycation
membrane, or by keeping a low-swelling gel network in the core. The
latter capsules are made from an alginate rich in guluronic acid
both in the core and in an outer coating, and with anisotropic distribution
of the polymer material in the core where the concentration at the
surface is higher than that in the centre of the capsule. Some functional
properties of these capsules, such as porosity, have also been studied.
(C) 1996 Elsevier Science Limited},
added-at = {2011-11-04T13:47:04.000+0100},
address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5
1GB},
author = {Thu, B. and Bruheim, P. and Espevik, T. and Smidsrod, O. and SoonShiong, P. and Skjak-Braek, G.},
authoraddress = {UNIV TRONDHEIM,NORWEGIAN INST TECHNOL,DEPT BIOTECHNOL,NORWEGIAN BIOPOLYMER
LAB,N-7034 TRONDHEIM,NORWAY. ; VIVORX INC,SANTA MONICA,CA 90404.},
biburl = {https://www.bibsonomy.org/bibtex/220d25c53952db2ea81cefa80fb900781/pawelsikorski},
citedref = {CHICHEPORTICHE D, 1988, DIABETOLOGIA, V31, P54 ; DUBOIS M, 1956, ANAL
CHEM, V28, P350 ; DUFF RG, 1985, TRENDS BIOTECHNOL, V3, P167 ; ESPEVIK
T, 1993, EUR J IMMUNOL, V23, P255 ; FLORY PJ, 1953, PRINCIPLES POLYM
CHE, P576 ; FRITSCHY WM, 1991, DIABETES, V40, P37 ; GOOSEN MFA, 1985,
BIOTECHNOL BIOENG, V27, P146 ; GOOSEN MFA, 1989, J MEMBRANE SCI,
V41, P323 ; HAUG A, 1964, 30 NORW I SEAW RES, P25 ; LIM F, 1980,
SCIENCE, V210, P908 ; LOWRY OH, 1951, J BIOL CHEM, V193, P265 ; MARTINSEN
A, 1989, BIOTECHNOL BIOENG, V33, P79 ; MARTINSEN A, 1992, BIOTECHNOL
BIOENG, V39, P186 ; MIKKELSEN A, 1995, BIOPOLYMERS, V36, P17 ; MOE
ST, 1993, MACROMOLECULES, V26, P3589 ; OTTERLEI M, 1991, J IMMUNOTHER,
V10, P286 ; POTTER K, 1993, CARBOHYD RES, V246, P43 ; SKJAKBRAEK
G, 1989, BIOMEDICAL BIOTECHNO, P345 ; SKJAKBRAEK G, 1989, CARBOHYD
POLYM, V10, P31 ; SMIDSROD O, 1974, FARADAY DISCUSS, V57, P263 ;
SMIDSROD O, 1990, TRENDS BIOTECHNOL, V8, P71 ; SOONSHIONG P, 1991,
TRANSPLANT P 1, V23, P758 ; SOONSHIONG P, 1993, P NATL ACAD SCI USA,
V90, P5843 ; STOKKE BT, 1991, MACROMOLECULES, V24, P4637 ; STOKKE
BT, 1993, CARBOHYD POLYM, V21, P39 ; TANAKA H, 1984, BIOTECHNOL BIOENG,
V26, P53 ; TANAKA T, 1979, POLYMER, V20, P1404 ; THU B, 1996, BIOMATERIALS,
V17, P1031 ; VANDER AJ, 1990, HUMAN PHYSL, P107 ; YUET PK, 1993,
FUNDAMENTALS ANIMAL, P79},
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intrahash = {20d25c53952db2ea81cefa80fb900781},
isifile-dt = {Article},
isifile-ga = {UM081},
isifile-j9 = {BIOMATERIALS},
isifile-nr = {30},
isifile-pi = {OXFORD},
isifile-sc = {Engineering, Biomedical; Materials Science, Biomaterials},
isifile-tc = {102},
issn = {0142-9612},
journal = {Biomaterials},
keywords = {; ;; [ISI:] acid alginate; beads; cytokine functional gel immobilization insulin insulin; islets; material; microcapsules; microencapsulation; production; properties; release; swelling; transplantation},
language = {English},
month = JUN,
number = 11,
owner = {phpts},
pages = {1069 -- 1079},
publisher = {ELSEVIER SCI LTD},
size = {11 p.},
sourceid = {ISI:A1996UM08100003},
timestamp = {2011-11-04T13:47:26.000+0100},
title = {Alginate polycation microcapsules .2. Some functional properties},
volume = 17,
year = 1996
}