Ice in and of itself isn't slippery – it becomes slippery when friction causes a thin layer of liquid water to form on top of it. Scientists have now applied that same basic principle to an injectable medication that could be used to treat osteoarthritis.
Presently, a natural polysaccharide known as hyaluronic acid (HA) is often injected into arthritic joints, in order to boost lubrication between bones. While it does work to an extent, it quickly degrades after its initial application.
Seeking a more persistent alternative, a team from China's Southeast University used a microfluidic device to create tiny gel particles made up of HA and a longer-lasting compound called methacrylate anhydride. Those particles were coated with another compound by the long name of 2-methylacryloyloxyethyl phosphorylcholine. It contains positively and negatively charged chemical groups, which attracted a thin layer of water onto the surface of the particles, making them very slippery – just like ice.
The scientists also loaded the particles' pores with an anti-inflammatory drug, with the idea being that the medication would be slowly and continuously released in a liquid environment.
When the gel particles were injected into the knee joints of rats with early-stage osteoarthritis, those joints exhibited better lubrication, less cartilage destruction, less friction and less inflammation than those of an untreated control group. Additionally, the treated rats expressed higher levels of collagen II and aggrecan, both of which are indicators of healthy joint cartilage.
Further experiments will be necessary before clinical trials on humans can begin. The research is described in a paper that was recently published in the journal ACS Nano.
Source: American Chemical Society
