Sustainable yarn made from crab shells and seaweed

An international team of researchers from Aalto University, the University of São Paulo and the University of British Columbia developed a new type of biobased fibre, made from crab shells and seaweed.

To be exact, the material is made from chitin, a compound found in residual blue crab shells, and alginate, which was extracted from seaweed. The chitin gives the yarn its strength, while the alginate provides flexibility. The yarn is sturdy and has antimicrobial properties.

The team wanted to make a fibre that combined the antimicrobial properties of chitin with seaweed alginate, which forms strong gels. When a solution of alginate contacts a suspension of chitin nanofibers, the alginate wraps around the chitin nanoparticles, forming fibrils that align in parallel as the thread is drawn upward.

Alginate dissolves readily in water. Brown algae have alginic acid in its cell walls, which can be converted to sodium alginate. The blue crab shells were ground and purified; then the material was partially deacetylated using simple procedures.

Potentially, the material could be used for threads for surgical procedures or medical meshes.

Photo: Rafael Grande / Aalto University