Ice-Inspired Lubricant Improves Osteoarthritis Symptoms in Rats

For professional ice skaters an ultrathin, super-lubricating layer of water on the ice’s surface is essential to achieve their graceful glides. Inspired by this surface, researchers have developed a treatment for osteoarthritis that enhances lubrication and reduces friction and inflammation in a rat model of the disease.

Osteoarthritis is characterized by persistent inflammation and degeneration of cartilage in the joints. Anti-inflammatory drugs can help relieve pain and inflammation, but long-term use can reduce their effectiveness or cause gastrointestinal problems. Yuanjin Zhao and colleagues wanted to develop drug delivery particles that, when injected into a joint, could safely enhance lubrication and decrease inflammation.

The researchers based their particles on hyaluronic acid (HA), this molecule degrades rapidly inside the body. So the researchers used a microfluidic device to make tiny methacrylate anhydride-HA gel particles, which they reasoned might be stronger and persist longer in the body than an HA solution. To enhance the lubrication of the particles, the team coated them with 2-methacryloyloxyethyl phosphorylcholine (MPC), which has positively and negatively charged chemical groups that attract a thin layer of water, similar to ice. In addition, the particles’ pores were loaded with an anti-inflammatory drug, which could be slowly and continuously released. The researchers then injected drug-loaded HA-MPC particles into the knee joints of rats with early-stage osteoarthritis. The joints of treated rats were more lubricated and had less cartilage destruction, joint friction and inflammation compared with a control group. The treated rats also expressed higher levels of collagen II and aggrecan, two markers of healthy cartilage. The particles have great potential for clinical applications, but first they must undergo additional animal and biosafety tests, the researchers say.


Lei Yang, Lingyu Sun, Han Zhang, Feika Bian, Yuanjin Zhao. Ice-Inspired Lubricated Drug Delivery Particles from Microfluidic Electrospray for Osteoarthritis Treatment. ACS Nano, 2021; 15 (12): 20600 DOI: 10.1021/acsnano.1c09325

American Chemical Society. “An ice-inspired lubricant improves osteoarthritis symptoms in rats.” ScienceDaily. ScienceDaily, 13 January 2022. <>.

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