Called a shape-memory polymer (SMP) and developed by a team at Texas A&M University in the US, this biodegradable material can be used to fill in gaps in a damaged face and act as a scaffold to guide the growth of existing bones.
The researchers made their shape-memory polymer by linking molecules of another material – polycaprolactone, or PCL – and whipping it into a foam. According to Jackie Hong at Motherboard, the material is soft and easy to mould when heated to 60°C (140°F), and sets when it’s cooled to body temperature without becoming brittle. It can be used in 3D printing and moulding, which means it can be shaped into extremely precise models and bone scaffolds, and it’s full of tiny holes like a sponge, which allows bone-producing cells called osteoblasts to collect inside and grow.
According to Hong, the researchers enhanced this osteoblast-growing effect by coating their SMP material in polydopamine – a different kind of polymer substance that helps bind existing bones to the SMP scaffold, and has been shown in previous studies to encourage the growth of osteoblasts. Over a three-day trial, their coated SMP scaffold grew five times more osteoblasts than their uncoated scaffold.
The team presented the new material at the 248th National Meeting & Exposition of the American Chemical Society in San Francisco earlier this month.
“The work we’ve done in vitro is very encouraging,” study leader Melissa Grunlan said in a press release. She said they’ll now test the polymer on animals suffering from bone defects in their heads and faces, and if that goes well, they’ll progress to clinical trials.
“Instead of invasive surgeries gathering autograft tissues, a surgeon can simply heat up the polymer, shape it so it perfectly fills out the defect (potentially with a 3D printer), pop it in place and let it cool down,” says Hong at Motherboard. “The patient’s bone cells would then start growing within the pores of the polymer, and since it’s biodegradable, the scaffold would gradually disappear, leaving behind the newly-formed bone.”