The Power of the Sea
Algin, an anionic heteropolysaccharide extracted from natural brown algae, is composed of β-(1–4) linked D-mannuronic acid and α-L-guluronic acid units. Along its polymer chain, alginate has regions rich in sequential mannuronic acid units, guluronic acid units and regions in which both monomers are equally prevalent. Alginate can form strong hydrogels in the presence of divalent cations, such as Ca2+, that interact with the carboxylic groups present in the alginate backbone to form ionic crosslinks. The freeze-dried matrix of natural algae fibres acts like a carrier and releases its active ingredients to the skin immediately after moistening the spongy structure.