Periosteum is a membrane of soft tissue that covers the outer surface of most bones in the body. Consisting of a complex combination of collagen, elastin and other structural proteins, it is an incredibly resilient material that gives bones extra strength under high impacts. Now, for the first time, researchers have mimicked these properties in a "smart" fabric that could serve as the basis for advanced functional materials with applications in everything from safety and transport, to medicine.
Biomedical engineers at the University of New South Wales (UNSW) started by mapping the complex tissue architectures of the periosteum for the first time. The team, led by UNSW's Paul Trainor Chair of Biomedical Engineering, Professor Melissa Knothe Tate, then visualized the structure in 3D on a computer and scaled up the key components of the tissue to produce proof of concept prototypes using a state-of-the-art computer-controlled jacquard weaving loom.
Since the fibers of collagen and elastin are too small to fit into the loom, the team scaled things up and swapped them for elastic material, which mimics elastin, and silk, which mimics collagen. They then wove a series of textile swatch prototypes using specific combinations of "collagen" and "elastin" in a design that mimics the twill pattern of periosteum's weave. The swatches were then subjected to mechanical testing, in which they exhibited similar properties to their natural inspiration.
"The result is a series of textile swatch prototypes that mimic periosteum's smart stress-strain properties," says Professor Knothe Tate. "We have also demonstrated the feasibility of using this technique to test other fibers to produce a whole range of new textiles."
Having found success with producing a proof of concept, the researchers say they are now ready to start producing fabric prototypes that could be used in everything from protective clothing that stiffens when exposed to high impacts, to "intelligent" compression bandages for deep-vein thrombosis that respond to the wearer's movement. A tire manufacturer has also proposed a titanium weave that could lead to new-generation steel-belt radials that are thinner, stronger and safer.
However, it is in the medical field that the team is focusing development of the technology, for which a patent is pending in Australia, the US and Europe.
"Our longer-term goal is to weave biological tissues – essentially human body parts – in the lab to replace and repair our failing joints that reflect the biology, architecture and mechanical properties of the periosteum," says first author of the study and biomedical engineering PhD candidate, Joanna Ng.
With the help of a development grant from Australia's National Health and Medical Research Council (NHMRC), the team will continue their research alongside the Cleveland Clinic and the University of Sydney's Professor Tony Weiss with the goal of developing and commercializing prototype bone implants for pre-clinical research within the next three years.
The team's research appears in Scientific Reports.