This is how MIT Engineers make Better Hydrogel for Artificial Tendons from Lobster Underbellies.
A recent experiment of MIT engineers group found out a new, stretchy hydrogel inspired by lobster underbellies. Lobster underbellies have a unique capacity to resist and long durable. The new hydrogel mimics the structure of lobster underbellies. The engineers are now hoping to use the hydrogel for artificial ligaments and tendons.
Inspiration and Core Team
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In 2019, a group of MIT engineers underwent research on lobster underbellies structure. They reported that the special thin, translucent membrane of a lobster underbelly has special characteristics: extremely tough yet stretchy and flexible. They came to the conclusion that that membrane is made from nature’s toughest hydrogel. This hydrogel in their underbelly protects the lobster as a shield, helping to swim swiftly. This research made a sensation, that in future another group of MIT engineers finally created that hydrogel alike material artificially.
The core MIT team includes postdocs Jiahua Ni and Shaoting Lin, graduate students Xinyue Liu and Yuchen Sun, prof. Raul Radovitzky (aeronautics & astronautics), prof. Keith Nielson (chemistry), prof. Xuanhe Zhao, former research scientist David Veysset PHD’16 (Stanford University), assistant prof. Zhao Kin from Syracuse University along with Alex Hsieh of the Army Research Laboratory.
The scientists have tested the resulted material. It successfully ran tests like stretching capacity and impact, and it mimicked the lobster underbelly hydrogel. According to the MIT team, the new material could be to make artificial tendons and ligaments.
Old and New Experiment
In 2019’s experiment Zhao’s team developed a new gelatin-glass-like material made of primary water and cross-linked polymer. The team tested the new material fabricating from ultra-thin fibers of the hydrogel. When they stretched the material the fibers aligned inlined and gathered like a straw, increasing new fatigue resistance.
Lin said: “At that moment, we had a feeling nanofibers in hydrogels were important and hoped to manipulate the fibril structure so that we could optimize fatigue resistance.” Now this time to make their new material better, Lin’s team used electro-spinning. Where the new material was put in a high-voltage electric charge and nanofibers from the polymer solution formed a flat film. The nanofibers measured 800 nanometers each. Later the nanofibers were placed in the high-humidity chamber. This helped the fibers to become interconnected and sturdy. Now the fibers were moved to high temperature to become a crystalize structure.
Comparison to Lobster Underbelly
However, the idea to compare it to lobster underbelly hydrogel was struck to Lin’s head from Ming Guo’s study. Guo, a mechanical engineer faculty studied the mechanical properties of lobster’s underbelly. He discussed the structure of that particular underbelly membrane. According to Guo, the membrane is consists of chitin stacked at a 36-degree angle, like a twisted plywood staircase. This typical structure is known as bouligand structure, which developed the lobster underbelly’s extreme stretch and strength.
This study helped Lin to compare both to understand more of the properties. According to Lin: “We learned that this bouligand structure in the lobster underbelly has high mechanical performance, which motivated us to see if we could reproduce such structures in synthetic materials.
Finally, the core team gathered and started to make the new material as the underbelly membrane. The especially gave the material angle structure. This time too using electro-spinning with five films putting in a 36-degree angle. The new crystallized material had measured 9 square cm and about 30-40 microns thick-like a small piece of scotch tape.
MIT Engineers to Make Better Hydrogel: Conclusion
With many micro ballistic impacts tests, velocity tests, the team presented the new material. However, the core team positively hopes that their new material will become used to artificial tendons. Lin said: “For a hydrogel material to be a load-bearing artificial tissue, both strength and deformability are required. Our material design could achieve these two properties. This whole result is published today in the journal Matter. The research is co-supported by MIT and U.S Army Research Office through Institution for Soldier Nanotechnologies in MIT.
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