Hokkaido University team developed a gel that can grow with help from nutrients and heavy load, just like muscles built from nutritional intake and weight-lifting. The gel can become sturdy by repeated “training” and there are hopes for it to be applied widely in the materials field to support long human life. Results were published in the electronic version of Science magazine dated February 1, 2019.
In general, durability of metal and rubber would decrease when heavy loads are applied. To resolve this shortcoming, research to develop tough artificial material is taking place around the world.
The team at Hokkaido University Graduate School of Life Science, Laboratory of Soft & Wet Matter consists of Prof. Jian Ping Gong, Assistant Prof. Tasuku Nakajima, Doctoral Candidate/JSPS Research Fellow Takahiro Matsuda and others. They focused on the double network gel (DN gel) which is known for being a tough material, despite the fact that 90% of its content is made up of water. DN gel is a mesh polymer, but is a combination of fragile mesh and flexible expandable mesh. When heavy load is applied on it, the fragile mesh falls apart. It is also known for its trait to take in monomers.
When heavy load is applied, Prof. Gong and her team thought that the gel’s internal structures would get destroyed to cause polymerization of monomers, which would trigger the synthesis of new mesh polymers. Consequently, the gel would become tougher. The group had artificially applied force to the DN gel that took in nutritional monomers and the group let it grow into a new DN gel. As a result, the gel’s strength grew 1.5 times and its stiffness had improved 23 times. As the team repeatedly conducted experiments to stretch the new DN gel with weight inside a container filled with liquid, the gel grew tougher and was able to lift the weight higher.
According the to the research team, there has never been a self-growing gel that can fortify itself through training. There are high hopes for the gel to be applied to medicine related to long life and industrial materials. This research was conducted as part of the ImPACT (Impulsing Paradigm Change through Disruptive Technologies) program initiated by the Council for Science, Technology and Innovation (CSTI) at the Prime Minister’s Cabinet.
Hokkaido University Press Release
Laboratory of Soft & Wet Matter