Self-healing bioplastic – just add water
Imagine if things like undersea cables or medical implants could simply heal themselves back together if severed – it would certainly be easier than having to go in and fix them. Well, scientists at Pennsylvania State University are bringing such a possibility closer to reality. They've created a moldable polymer that heals itself when exposed to water – and it's based on squid sucker ring teeth.
Led by Prof. Melik Demirel, the researchers started by studying sucker ring teeth collected from squid in various locations around the world. Although the exact composition of the teeth varied between species, it was found that the same proteins which allow them to self-heal were always present.
The yield of these proteins were quite low per squid, however, meaning that many animals would have to be processed in order to obtain a usable amount. Instead, the scientists used bacteria to produce those same proteins in the lab, for use in their polymer.
The result is actually a copolymer, as it consists of two parts – a structured portion made up of strands of amino acids connected by hydrogen bonds, and the actual self-healing portion which is more amorphous.
In lab tests, a sample of the material was first cut in two, and then had warm water and slight pressure applied at the severance point. This caused the two pieces to join back together into one. When subjected to weight-suspension tests, the healed sample was found to be just as strong as it was before being cut.
"Maybe someday we could apply this approach to healing of wounds or other applications," says Demirel. "It would be interesting in the long run to see if we could promote wound healing this way so that is where I'm going to focus now."
A demo of the polymer can be seen in the video below.