A lubricant that doesn’t wash away could ease arthritis pain in knees and shoulders , keep artificial joints working smoothly , and even make contact lenses more comfortable .
Biomedical engineers discovered a way to bind the lubricant to a sticky manmade molecule that then essentially locks it in place on the surface of cartilage and eye tissues .
“ What I like about this concept is that we’re mimicking natural functions that are lost , using synthetic materials , ” says Jennifer H. Elisseeff, professor of ophthalmology , biomedical engineering , and materials science at Johns Hopkins University .
Scientists have long known that hyaluronic acid (HA) is abundant in the fluid that surrounds joints like knees , shoulders , and wrists .
HA is an important component for naturally lubricating tissues; one form of the biochemical also reduces inflammation and protects cells from metabolic damage .
Diseased , damaged , or aging joints in hips, knees, shoulders , and elbows often have far lower concentrations of HA , presumably because a protein that binds HA molecules to joint surfaces is no longer able to retain HA where it is needed .
HA injections , a method known as viscosupplementation , have become popular treatments for painful joints . Without a way to retain HA at the site , however , the body’s natural cleaning processes soon wash it away .
For a new study , published online in the journal Nature Materials , Elisseeff looked at molecules known as HA-binding peptides (HABpeps) , which stick to HA .
In the laboratory , using HABpep as a chemical handle , she and her colleagues used a second , synthetic molecule , polyethylene glycol , to tie HA onto surfaces that included natural and artificial cartilage and eye tissue .
Tests on tissues and in animals show that the bound HA didn’t easily wash away . It also reduced friction as successfully as when the tissues were immersed in a bath of unbound HA .
When researchers injected a HABpep designed to attach to cartilage in rat knees , then injected HA, that HA stuck around 12 times as long as it did in rats that hadn’t been given HABpep , suggesting that these peptides could be a promising addition to viscosupplementation .
The HABpep-polymer system could also be useful as an eyedrop solution to improve contact lens comfort and keep damaged eye tissues lubricated .
The National Institute on Aging, the National Institute of Arthritis and Musculoskeletal and Skin Diseases , the Arthritis Research Foundation , the Department of Defense , the Wallace H. Coulter Foundation , the Ort Philanthropic Fund , and Research to Prevent Blindness funded the study .
《Enhanced lubrication on tissue and biomaterial surfaces through peptide-mediated binding of hyaluronic acid》, Published on Journal 《NATURE MATERIALS》in August , 2014 .