University of British Columbia researchers have cast artificial proteins into a new solid biomaterial that very closely mimics the elasticity of muscle.
The approach, detailed in the current issue of the journal Nature, opens new avenues to creating solid biomaterials from smaller engineered proteins, and has potential applications in material sciences and tissue engineering.
"There are obvious long-term implications for tissue engineers," says Hongbin Li, associate professor in the Dept. of Chemistry. "But at a fundamental level, we've learned that the mechanical properties we engineer into the individual proteins that make up this biomaterial can be translated into useful mechanical properties at the larger scale."
Li, Canada Research Chair in Molecular Nanoscience and Protein Engineering, and UBC colleague John Gosline, professor in the Dept. of Zoology, engineered the artificial proteins to mimic the molecular structure of titin.
Titin – also known as connectin – is a giant protein that plays a vital role in the passive elasticity of muscle. The engineered version-which resembles a chain of beads-is roughly 100 times smaller that titin.
The resulting rubber-like biomaterial showed high resilience at low strain and was tough at high strain — features that make up the elastic properties of muscles.
"A hallmark of titin-like proteins is that they unfold under a stretching force to dissipate energy and prevent damage to tissues by over-stretching," says Gosline. "We've been able to replicate one of the more unique characteristics exhibited by muscle tissues, but not all of them."
The mechanical properties of these biomaterials can be fine-tuned, providing the opportunity to develop biomaterials that exhibit a wide range of useful properties – including mimicking different types of muscles. The material is also fully hydrated and biodegradable.
This research is supported by the Canadian Institutes of Health Research, the Canada Research Chairs program, the Canada Foundation for Innovation, the Michael Smith Foundation for Health Research, and the Natural Sciences and Engineering Research Council of Canada.