Biocompatible alginate from freshly collected Laminaria pallida for implantation

A simple procedure is described for the extraction and purification of algi nate from the inner stipes of the kelp Laminaria pallida. Alginate yield wa s about 10-15% of the dry mass, with a 70:30 mannuronic/guluronic acid rati o. Analysis of the purified alginate revealed a low polyphenol content whil e proteins were below detection level. The purified alginate was highly vis cous, with 10-15 mPa s and 281 mPa s for a 0.1% and 0.5% solution, respecti vely, indicating a very high molecular mass (larger than 250 kDa). Bead for mation occurred in the presence of divalent cations. but also in the presen ce of artificial serum (FCSIII) without added divalent cations. The biocomp atibility 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 c apsule of BB/OK rats. There was no evidence for significant mitogenic activ ity or fibrotic reaction. Biocompatibility of the alginate was also demonst rated by the encapsulation of human chondrocytes into Ca2+ cross-linked alg inate beads. Immobilized chondrocytes grew and remained functional (i.e. th ey produced collagen).