First they dissolved silk in alcohol, then poured the solution into moulds shaped like the implants and baked them.
In tests on rats, the screws were hard enough to cut their own threads through bone, just as alloy screws do.
Although there are biodegradable polymer alternatives, these too have drawbacks. They can trigger inflammation and are too soft to cut their own thread through bones – a hope has to first be drilled.
“We envision a whole set of orthopaedic devices for repair based on this – from plates and screws to almost any kind of device you can think of where you don’t want hardware left in the body,” Kaplan told the BBC. “They don’t interfere with X-rays, they don’t set off alarms and they don’t cause sensitivity to cold.”
He also said that silk could also be used to deliver antibiotics to prevent infection, or drugs that enhanced bone regrowth.
Bill Condie is a science journalist based in Adelaide, Australia.
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