An environmentally friendly alternative to synthetic plastics

Researchers at Harvard’s Wyss Institute have developed a method to carry out large-scale manufacturing of everyday objects using a fully degradable bioplastic isolated from shrimp shells.

The advance was reported online last week in Macromolecular Materials & Engineering.

The objects exhibit many of the same properties as those created with synthetic plastics, but without the environmental threat. It also trumps most bioplastics on the market today in posing no threat to trees or competition with the food supply.

Most bioplastics are made from cellulose, a plant-based polysaccharide material. The Wyss Institute team developed its bioplastic from chitosan, a form of chitin. Chitin is a long-chain polysaccharide that is responsible for the shells of shrimps among other things.

Most available chitin comes from discarded shrimp shells, and is either thrown away or used in, for example, fertilizers, cosmetics, or dietary supplements. However, material engineers have previously not been able to fabricate complex 3D shapes using chitin-based materials.

The Wyss Institute team, led by Postdoctoral Fellow Javier Fernandez, Ph.D., and Founding Director Don Ingber, M.D., Ph.D., developed a new way to process the material so that it can be used to fabricate large 3D objects with complex shapes using traditional casting or injection moulding manufacturing techniques.

 In addition, their chitosan bioplastic breaks down when returned to the environment within about two weeks, and it releases rich nutrients that efficiently support plant growth.

“You can make virtually any 3D form with impressive precision from this type of chitosan,” said Fernandez.

The next challenge is for the team to continue to refine their chitosan fabrication methods so that they can take them out of the laboratory, and move them into a commercial manufacturing facility with an industrial partner.

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