Self-healing and flexible medical devices are the next big thing in medical technology. Biotechnology experts have been attempting to develop successful devices with these abilities for years. By looking at squid teeth, researchers found synthetic protein-powered medical devices created from repeated sequences of proteins could be possible.
These are proton conductivity measurements of protein membranes using impedance spectroscopy. (Source: Abdon Pena-Franchesch)
"The question we had was whether we could make flexible and self-healing medical devices to work on protons the way biological systems do," said Melik Demirel, Pierce Development Professor and professor of engineering science and mechanics. "Nature knows how to transfer protons, for example in charging biological energy known as ATP (adenosine triphosphate)."
Proton transfer is a major part of most fuel cells used in these medical devices. Nafon, an ion-transfer membrane made from polymers is often used in these cells, but they are not compatible with biomedical devices. The researchers hope that they can develop these cells to be biocompatible for battery-free medical devices.
These new, squid-ring-teeth inspired polymers are the key to these types of fuel cells. These polymers are biocompatible, self-healing, flexible and stretchable. Researchers develop these fuel cells to be bio-synthetic by choosing the DNA sequences. This means that these proteins can have customized conductivity and flexibility. The material must have 60 percent water for the proton conduction to operate.
The problem with these protons is that they are not as powerful as the polymer conductors. Researchers are attempting to find a way to strengthen proton conductivity.
The new proteins are made of amino acids, and also have tandem repeats in their molecular makeup, allowing the researchers to create proteins with 4, 7, 11 and 25 repeats. They then used these materials to create thin films for biomedical uses.
There are some natural biological proton conductors, silk, keratin, collagen, melanin and bovine serum albumin. But the synthetic protein was proven to be the best conductor out of all the natural proteins.
"Our goal is to understand the design rules of biological proton conductors so that we can create a synthetic protein that is as good as a nonbiocompatible proton conductor," said Demirel. "Then, can we make a self-healing, flexible pacemaker from this type of device? Can we make protonic bioelectronic devices?"
The paper on this research was published in Chemistry of Materials.
