Researchers Use Rare Iron Mineral Found In ‘Wandering Meatloaf’ Mollusk Teeth For Bioink 3D Printing
Researchers from Northwestern University discovered a rare type of iron ore in mollusk teeth that was previously only seen in rocks.
The mineral, Santabarbaraite, was found in the stylet – a long, hollow structure that connects a tooth to a soft membrane – in a mollusk Cryptochiton stelleri, also known as the “wandering meatloaf” mollusk because of its brown color. reddish, its shape and size.
The researchers took advantage of this discovery to develop bioinks suitable for 3D printing that mimic the strength, stiffness and connection properties of the mollusk pen.
“This mineral has only been observed in geological specimens in very small amounts and has never been seen before in a biological setting,” said Derk Joester, lead author of the study and associate professor of science and technology. materials engineering at Northwestern’s McCormick School of Engineering.
“It has a high water content, which makes it solid with a low density. We think it might harden the teeth without adding a lot of weight.
The “wandering meatloaf” mollusk
Nicknamed the “Wandering Meatloaf” due to its reddish-brown color and body that can grow up to 14 inches in length, the mollusk Cryptochiton stelleri is also known as the giant Pacific chiton and giant rubber chiton.
Chiton teeth are said to be made from one of the hardest materials known in nature, designed to withstand the chewing of rocks for food. Chiton’s teeth are attached to a soft, flexible tongue-shaped radula that scrapes rocks to collect algae and other food.
The researchers were particularly interested in the stylet, which connects the ultra-hard tooth to the soft radula, and believe that there is much to be learned from this natural material.
“The stylet is like the root of a human tooth, which connects the cusp of our tooth to our jawbone,” Joester said. “It is a tough material made up of extremely small nanoparticles in a fibrous matrix made up of biomacromolecules, similar to the bones in our body.”
To examine a tooth from a Cryptochiton stelleri, the researchers used Mössbauer’s synchrotron spectroscopy capabilities at the Argonne National Laboratory Advanced photon source and leveraged transmission electron microscopy at Northwestern’s Characterization and experimentation at atomic and nanometric scales (NUANCE) Center.
Thanks to this, they found santabarbaraite scattered throughout the upper stylet of the chiton, a rare iron mineral that has so far only been seen in rocks.
Leverage Santabarbaraite for 3D printing
After discovering the rare mineral in the chiton’s stylus, the researchers set out to recreate the material in a bio-ink designed for 3D printing. They combined iron and phosphate ions with a biopolymer derived from chiton to create a reactive ink that “printed well” when mixed immediately before printing.
“As the nanoparticles form in the biopolymer, it becomes stronger and more viscous,” Joester said. “This mixture can then be easily used for printing. Subsequent air drying leads to the final hard and rigid material.
The ability to replicate the strength, stiffness and connectivity properties of the chiton’s stylus through bioink development and 3D printing holds promise for future learning and the development of nature-inspired materials, Joester believes.
“We have been fascinated by the chiton for a long time,” he said. “Mechanical structures are only as good as their weakest link, so it’s interesting to learn how the chiton solves the engineering problem of connecting its ultra-hard tooth to a soft underlying structure.
“This remains a significant challenge in modern manufacturing, so we look to organisms like the chiton to understand how this is done in nature, which has had a few hundred million years to develop.”
More information about the study can be found in the article titled “Persistent polyamorphism in chiton’s tooth: from a new biomaterial to inks for additive manufacturing”, which will be published in the journal Proceedings of the National Academy of Sciences later this week.
Researchers and scientists are increasingly seeking to replicate materials and processes found in the natural world that exhibit desirable properties not obtainable by purely artificial means. The development of bio-ink for 3D printing plays a key role in harnessing these properties, and there has been a plethora of recent discoveries in this area.
Applications of soft robotics have received special attention, with researchers from Rutgers University have camouflage-ready 3D printed robots inspired by adaptable cells found in squid, cuttlefish and octopus, and Yamagata University scientists who developed a 3D printed actuator that could form the basis of a soft jellyfish-like robot. Elsewhere, Dutch scientists have 3D printed a new adhesive material with a microscopic mushroom-shaped design that could be deployed to help soft robots walk vertically.
The medical industry has also seen new nature-inspired developments, including new 3D printed dragonfly-inspired ‘spiky joints’ for the treatment of wrist injuries and 3D printed micro-needle patches for drug delivery. painlessly reproducing the hierarchical structure of a limpet.
Other 3D printing research developments and applications inspired by natural materials include biomimetic cell-like structures with unique energy absorption capabilities based on the skeleton of a cuttlefish, 3D printed concrete structures inspired by Lobster shell patterns and shatterproof materials based on the natural properties of spider webs.
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Featured Image Shows Cryptochiton stelleri or “wandering meatloaf” mollusk in nature. Photo by Jerry Kirkhart.