Plastic bottle parts slash cost of creating artificial limbs

PLASTIC bottles can be turned into prosthetic limbs that are 40 per cent lighter and thousands of pounds cheaper than existing models, scientists have discovered.

Two patients are now walking with artificial legs whose sockets are made from ground-down plastic that might otherwise have ended up in landfill.

Researchers at De Montfort University, Leicester, said the technique enabled a more exact fit around a patient’s stump than carbon or glass fibre models, and reduced the risk of infection.

At £10 a unit, it is 500 times cheaper than the standard price of £5,000.

Dr Karthikeyan Kandan said: “Upcycling of recycled plastics and offering affordable prostheses are two major global issues that we need to tackle.”

“There are some really scary statistics about how much plastic there is polluting our oceans and the planet. One of the biggest problems is that the plastic bottles cannot be recycled and reused for the same purpose, so it’s up to us to find new uses for them.”

Artificial limbs have previously been made from bulk plastic – high-density polyethylene – however, those were heavy and not durable.

The new design spins recycled polyethylene terephthalate (PET), from plastic bottles, into yarns 10 times stronger than bulk plastic.

These yarns are “knitted” into a porous socket that keeps patients cooler, particularly crucial in the case of diabetic amputees, who often sweat a lot.

This is a feature that neither carbon or glass fibre sockets – currently the best designs available – can boast. It takes around five one-litre Coca-cola bottles to make a prosthetic socket.

Funded by the Academy of Medical Sciences, the team fitted the PET yarn sock over the moulds of two amputees’ stumps, before heating the sockets to 230C (446F) for 20 minutes.

They were then flown to Jaipur in India and fitted to the patients. “Both patients were really impressed – they said the prosthetic was lightweight and easy to walk with, and it allowed air to flow to the rest of the leg,” said Dr Kandan.

His group is currently preparing a larger international trial of the new material which would give an evidence base allowing health chiefs to adopt the design for routine use.