Researchers Create 'Super Ice' With Cellulose Nanocrystals and a Designer Protein
Researchers bound cellulose nanocrystals into ice using a custom protein, producing a material they call BioPykrete that tested about 10 times stronger than ordinary ice, according to a report on work published in Colloids and Surfaces B: Biointerfaces.
In those tests, the material the report calls "BioPykrete" absorbed about 70 times more energy before breaking than regular ice, the report said.
The strengthening agent is cellulose, the main structural material in plants. In nanocrystal form, it acts as a microscopic reinforcement inside other materials, including ice, largely by preventing cracks from spreading easily. Earlier ice composites relied on larger, disordered wood-pulp fibers; the new work uses cellulose nanocrystals instead.
The second ingredient is a protein designated CBM3a-AFPIII, a combination of an antifreeze protein, or AFP, and a carbohydrate-binding module, or CBM. Its role is to act as glue, keeping the cellulose nanocrystals and the ice bonded together.
The researchers write that adjusting the recipe and the process could push the results further. "Optimizing solidification kinetics and freezing protocols, alongside developing diverse AFP-CBM variants, could yield even higher-strength composites," they write.
Beyond additional durability tests, the team wants to examine more closely how cracks travel through BioPykrete, to confirm that the strengthening mechanisms work as they expect.
Longer term, the approach could open a new range of materials for packaging, construction and other uses, based on pairing two unlikely compounds, ice and cellulose, through a custom protein. "By bridging the gap between recombinant protein design and structural engineering, we have developed a high-performance material specifically engineered for the rigors of the world's most extreme environments," the researchers write.