A stretchy new fabric made by linking together the proteins found in muscle tissue could provide a scaffold for growing new organs. It could also be used as a coating for bandages to help wounds heal quickly and with less scarring. The fabric was made in the laboratory of Kevin Kit Parker, a professor at Harvard’s School of Engineering and Applied Science.
When the body grows new tissue, cells secrete fibronectin–a strong, stretchy type of protein that acts as a supportive scaffold. The shape and structure that fibronectin adopts directs the subsequent growth of new cells, giving the resulting tissue the correct form.
Parker’s team creates the fabric by depositing fibronectin molecules on top of a water-repelling polymer surface. This causes the proteins, which are normally bundled up, to unravel. Next, the protein layer is stamped onto a dissolvable, water-attracting polymer sheet on top of a piece of glass. Adding water and warming the mixture to room temperature makes the proteins link together to form the fabric. It also dissolves the polymer so that the fabric can be peeled away and collected.
Other than building three-dimensional scaffolds for organ reconstruction, the new fabric could be embedded in bandages, accelerating wound healing and minimizing scar formation.
The material could also find other novel uses. An appealing feature is its unusual elasticity. The fibronectin protein, which forms the base thread of the fabric, is part of the molecular machinery that allows muscles to contract and relax.
“[Fibronectin] is compressed like a spring when you’re contracting your muscle, and when you relax, it pushes it back,” says Parker. This structure gives the fabric its elasticity, and allows it to be stretched up to 18 times its original length. “When you pull on the fabric, you unfold the proteins,” providing additional strength, says Parker.
Parker’s team is exploring the mechanical properties of the new fabric, examining its strength and stretchiness. The new stamping method could let them make larger, more complex fabrics. “The base technology is down,” says Parker. “Now we need to facilitate the spinout applications.”
In research published this week in The Lancet, the researchers demonstrate that the technology–a joint-shaped scaffold infused with a growth factor protein–works in rabbits. About a month after the implant, the animals began using their injured forelimbs again, and at two months the animals moved almost as well as similarly aged healthy rabbits. The study is the first to show that an entire joint can be repaired while being used.
“They used the potential of the body as a bioreactor, instead of doing everything in the petri dish,” says Patrick H. Warnke, a professor of surgery at Bond University. Warnke wrote a commentary on the Columbia study for The Lancet. While the connection between bone and the titanium in existing implants wears out over time, the hope for this alternative approach is that the new bone formed by the stem cells will create a more natural and durable connection, and that the scaffold itself would disintegrate over time.