Biocompatible alginate from freshly collected Laminaria pallida for implantation

Abstract

A simple procedure is described for the extraction and purification of alginate from the inner stipes of the kelp Laminaria pallida. Alginate yield was about 10-15% of the dry mass, with a 70:30 mannuronic/guluronic acid ratio. Analysis of the purified alginate revealed a low polyphenol content while proteins were below detection level. The purified alginate was highly viscous, with 10-15 mPa s and 281 mPa s for a 0.1% and 0.5% solution, respectively, indicating a very high molecular mass (larger than 250 kDa). Bead formation occurred in the presence of divalent cations, but also in the presence of artificial serum (FCSIII) without added divalent cations. The biocompatibility of the alginate was tested with the in vitro mice lymphocyte test as well as by implantation of Ba2+ cross-linked beads beneath the kidney capsule of BB/OK rats. There was no evidence for significant mitogenic activity or fibrotic reaction. Biocompatibility of the alginate was also demonstrated by the encapsulation of human chondrocytes into Ca2+ cross-linked alginate beads. Immobilized chondrocytes grew and remained functional (i.e. they produced collagen).

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

“…Although it is recognized that other purification protocols have been published, 24,27,28,31,33,34 we decided not to include them in this study for economical and practicality reasons. Specifically, although Zimmermann et al 34 published a purification method that used free-flow electrophoresis, we chose not to reproduce the described protocol because the procedure is expensive and difficult to perform on a large scale.…”

“…[23][24][25][26][27][28] To ensure the clinical application of alginate-based microencapsulation, however, the variability between purification protocols applied by independent laboratories must be reduced and a purity standard that conforms to current health regulations must be defined. To our knowledge, no comparative studies of presently applied methods for alginate purification have been published.…”

Characterizing the Three Different Alginate Type of Sargassum siliquosum

“…CaCl2 which is added in the Calcium Alginate extraction will build an "egg box" for more stabilized alginate (Yang et al, 2009). Both compounds, will be expected producing more yield by EDTA addition (Jork et al, 2000).…”

“…The acid, calcium and sodium alginate extract was prepared based on the methods of Jork et al (2000), Davis et al (2004), and Kim et al (2004),respectively. Prior to the extraction, the dried seaweed was depigmented with 85% ethanol until colourless.…”

Bioactive surfaces from seaweed-derived alginates for the cultivation of human stem cells

“…After long-time experience with the production of ultra-pure Bclinical-grade^alginates (Jork et al 2000;Zimmermann et al 2005) and extensive studies on alginate hydrogels in the context of immunoisolation of pancreatic cells, we focused on the specific bioactivation of alginate hydrogels for applications in tissue engineering. Early approaches with ultra-high viscous alginate surfaces were conducted with highly concentrated collagen I solution and used a pH shift for non-covalent coating (Gröhn et al 1997).…”