Sugar could repair artificial human joints

By Mark Waghorn via SWNS

Sugar could repair artificial human joints after a plastic coating containing the sweetener was developed by scientists.

It could prevent hip and knee replacements being damaged by wear and tear.

The material mimics how cartilage - the human body's 'shock absorber' - lubricates bones, allowing them to slide over one another.

It could also make cars and other machinery more durable.

"Our sugar-containing coating gives us an appealing new way of patching up damage to low-friction surfaces," saidsenior author professor Paul McGonigal, of Durham University.

"Hip and knee joints in our bodies stand up to decades of wear and tear thanks to the cartilage being repaired and replaced constantly.

"We have made materials that work in a similar way, but that are compatible with artificial joints.

"The components of our coatings are biocompatible, which makes them exciting prospects for use in medicine."

They could extend the lifespan of artificial joints.

Hip and knee implants normally loosen after 10 to 15 years.

They become painful - and have to be replaced. The covering may end the need for repeat surgery.

"We could also imagine developing a range of these materials that work in very different environments,"McGonigal said.

"Avoiding and repairing the damage caused by friction is equally important to ensure that cars and other machinery last for a long time."

The international team found rings of sugar helped the polymer latch on to surfaces and repair them.

They hope the coating could also reduce friction-caused energy waste in mechanical systems - making them more efficient.

In experiments, when it was rubbed away during use the sugar allowed it to reattach easily.

It then mimics cartilage - which uses water to make a slick surface that minimises wear and tear.

In the same way, the polymer coaxes a layer of water up - making it slippery and protecting surfaces as they are knocked.

It has a long molecular chain with positive and negative charges - using an effect similar to static electricity.

The sugar ring - attached to one end - anchors itself to a surface by docking with organic compounds called adamantanes.

Tests on titanium metal showed the coating - described in the journal Chem - is attracted to the surface.

The weak, non-permanent links that form are key to the repair process.

Co-author Dr. Yulong Sun, also from Durham, said: "Repair mechanisms are key to making materials that last a long time.

"Nature's low-friction materials regenerate when they are damaged.

"But until now we haven't had good repair mechanisms for artificial systems.

"To tackle this challenge, we need chemists and engineers to cooperate to design advanced coating technology."

In England and Wales about 160,000 hip and knee replacement procedures are performed each year.

Co-author Dr. Alyssa-Jennifer Avestro, of York University, said: "This is dynamic yet selective chemistry which looks like it could be an effective way to undo the negative effects of mechanical wear on joints and other surfaces.

"If our protective coating layer is worn off it's restored again without needing our intervention - thanks to targeted molecular recognition."