Premium
Inhomogeneous alginate gel spheres: An assessment of the polymer gradients by synchrotron radiation‐induced x‐ray emission, magnetic resonance microimaging, and mathematical modeling
Author(s) -
Thu Beate,
Gåserød Olav,
Paus Didrik,
Mikkelsen Arne,
SkjåkBræk Gudmund,
Toffanin Renato,
Vittur Franco,
Rizzo Roberto
Publication year - 2000
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(200001)53:1<60::aid-bip6>3.0.co;2-f
Subject(s) - polymer , chemistry , calcium alginate , porosity , spheres , relaxation (psychology) , glucuronic acid , ion , analytical chemistry (journal) , calcium , chromatography , organic chemistry , polysaccharide , psychology , social psychology , physics , astronomy
It has been previously demonstrated that calcium alginate gels prepared by dialysis often exhibit a concentration inhomogeneity being the polymer concentration considerably lower in the center of the gel than at the edges. Inhomogeneity may be a preferred structure in microcapsules due to low porosity and higher stability so that it is interesting to evaluate the polymer gradient in spherically symmetrical small alginate beads (1.0–0.7 mm diameter) obtained in different conditions. In this paper, two complementary techniques have been used to investigate this aspect. The concentration gradient of alginate has been analyzed by measuring both the spatial distribution of calcium ions in sections of alginate gel spheres, by means of x‐ray fluorescence spectroscopy, and the T 2 relaxation behavior on intact gel beads using magnetic resonance microimaging. The experimentally determined gradients from three‐dimensional gels provide data to reevaluate the parameter estimates in the recently reported mathematical model for alginate gel formation (A. Mikkaelsen and A. Elgsaeter, Biopolymers , 1995, Vol. 36, pp. 17–41). The model may account for the gels being less inhomogeneous when nongelling sodium or magnesium ions are added during gelation. © 2000 John Wiley & Sons, Inc. Biopoly 53: 60–71, 2000