Premium
The molecular weight cut‐off of microcapsules is determined by the reaction between alginate and polylysine
Author(s) -
Vandenbossche Geert M. R.,
Van Oostveldt Patric,
Demeester Joseph,
Remon JeanPaul
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260420316
Subject(s) - polylysine , chemistry , fluorescein isothiocyanate , calcium alginate , dextran , chromatography , nanocapsules , calcium , biophysics , polymer chemistry , nuclear chemistry , biochemistry , fluorescence , nanotechnology , materials science , organic chemistry , biology , nanoparticle , physics , quantum mechanics
Mammalian cells encapsulated in alginate‐polylysine microcapsules are used as artificial organs in cancer research and in biotechnology. These applications require microcapsules with a reproducible mol. wt. cut‐off. The high cost of the polycation, polylysine, requires an efficient preparation procedure. This article shows that the overall reported contact time of 5 minutes at ambient conditions should be increased several times in order to reach a maximal binding between the calcium alginate beads and 0.1% (w/v) polylysine solutions. An increase of the polylysine concentration from 0.0125% to 0.8% (w/v) resulted in a faster maximal binding, but the amount of polylysine bound increased also. Immersion of calcium alginate beads with a diameter of 750 μm, prepared from 1 mL alginate, in 30 mL of a 0.8% (w/v) polylysine solution, resulted in a polylysine spill of more than 89%. The time required to reach a maximal binding was related to the reaction temperature. The interaction zone between calcium alginate beads and fluorescein isothiocyanate‐labeled polylysine solutions was visualized with a confocal laser scanning microscope as a function of time. Microcapsules, prepared at 40°C with 0.1% (w/v) polylysine solutions with mol. wts. between 12 and 249.2 kD, were permeable for fluorescein isothiocyanate‐labeled dextran, mol. wt. 4.7, but not for 40.5 kD. Higher polylysine concentrations resulted in a membrane with a mol. wt. cut‐off lower than 4.7 kD. © 1993 John Wiley & Sons, Inc.