“Everybody’s always talking about ABS, PLA, HIPS, carbon nanotubes… All we are saying is give squids a chance!” – John Lennon and Yoko Ono on new plastics research at Penn State.
Though corn starch-based PLA has been one of the more environmentally sustainable materials used in FDM/FFF 3D printing, researchers at Penn State are looking for even more ecological alternatives. And the plastic they’ve found comes from an unlikely source: squid DNA. With funding from the Office of Naval Research and the Army Research Office, the team at Penn State has begun research into a protein complex within squid ring teeth (SRT) with 3D printing applications.
Melik C. Demirel, professor of engineering science and mechanics explains, “Most of the companies looking into this type of material have focused on synthetic plastics. Synthetic plastics are not rapidly deployable for field applications, and more importantly, they are not eco-friendly.” Instead, Demirel and his colleagues, including professor of chemical engineering Wayne Curtis, have begun sequencing genes from SRT.
Demirel continues, “We have the genetic sequence for six squid collected around the world, but we started with the European common squid.” In a paper published in Advanced Functional Materials, the team outlines how, using those sequences, they’ve been able to synthesize a number of proteins, including some that demonstrate a stable thermal response. Such thermoplastics can be melted and cooled, while maintaining their chemical purity. One of these thermoplastics include the SRT protein with the lightest molecular weight, which could be used in both traditional manufacturing processes, such as molding and casting, or as a feedstock for 3D printers.
To produce the material, the researchers inserted the genes for this SRT protein into E. coli, inducing the bacteria to produce plastic molecules. The resulting thermoplastic is semi-crystalline, can be made into a rigid or soft form, has a high tensile strength, and acts as a wet adhesive, so that it can stick to objects even while wet. The properties of the material can also be controlled during the manufacturing process and, due to its biological nature, it can be used in the fields of medicine and cosmetics.
As 3DPI’s Davide Sher has pointed out, the 3D printing materials market is set to surpass $1 billion by 2019. Because most plastics are derived from fossil fuels, like crude oil, there is no doubt that sustainable materials will hold a stake in this market. On the one hand, materials will be recycled from discarded prints or existing plastic refuse, but, to ensure a ready supply of eco-friendly materials, researchers are continuing to seek new ways to produce the stuff. 3DPI’s Shane Taylor explored one method in which a team at ETH Zürich uses a chemical catalyst to produce more PLA with greater efficiency.
Demirel explains that their study is an example of a larger picture of materials manufacturing, saying, “The next generation of materials will be governed by molecular composition—sequence, structure, and properties.” As strange as it sounds, plastic made from squid DNA may just be one among many of the unique materials developed by Penn State in the future. The professor’s research fits nicely with Penn State’s role in this next generation of materials as the head of the Consortium for Additive Manufacturing Materials (CAMM), funded by the National Institute of Standards and Technology (NIST) earlier this year.
