2/24/2026 Jeni Bushman
Ivan Racheff Professor Rosa Espinosa Marzal used a novel combination of imaging techniques to reveal that inferior joint lubrication in osteoarthritis stems from the mechanical instability of vesicle-dominated boundary films — overturning the long-held belief that vesicles are superior lubricants. These findings point to lamellar structures promoted by high-molecular-weight hyaluronic acid as a more effective source of lubrication, offering a more scientifically grounded foundation for developing future osteoarthritis therapies.
Written by Jeni Bushman
Researchers from The Grainger College of Engineering are the first to use a powerful combination of imaging techniques to visualize friction properties on soft interfaces in the context of osteoarthritis.
Osteoarthritis is the most common form of arthritis in the United States, caused by the breakdown of cartilage and compounded by a reduction in hyaluronic acid, which lubricates synovial joints. For years, scientists have recognized hyaluronic acid and phospholipids as key components of joint lubrication, but the exact mechanism tying them to osteoarthritis has been widely debated. Now, research from The Grainger College of Engineering at the University of Illinois Urbana-Champaign has addressed this hotly debated question using a powerful new methodology. Led by materials science professor Rosa Espinosa Marzal and published in Science Advances, their findings shed light on the mechanical instability of vesicle-dominated boundary films and may improve future therapies for osteoarthritis.
Espinosa Marzal’s interest in osteoarthritis began in 2017, when she was approached by members of the Rush University Medical Center orthopedics department about her work on tribological soft interfaces. Could her lab’s imaging capabilities examine cartilage at the molecular nanoscale?
“Rush asked us to look at the cartilage surface and help answer a question about some results they were seeing in patients,” Espinosa Marzal said. “The surface structure of cartilage is quite complex. For the next study, we created a simpler system with some elements of real cartilage. Our first paper in 2023 was more about structure than lubrication, and it generated a lot of interest. People wanted to know, ‘What’s the next chapter of this story? What happens with friction?’ This study was to answer those curiosities.”
Led by graduate student Kangdi Sun and with collaboration from Professor Mark Rutland of the KTH Royal Institute of Technology Stockholm, the group used their existing model system to investigate differences in lubrication behavior between healthy joints and osteoarthritis-mimic joints. By combining atomic force microscopy (AFM) with quartz crystal microbalance (QCM) measurements and in situ microscopic friction visualization, they determined that inferior lubrication in conditions mimicking osteoarthritis stems from the mechanical instability of vesicle-dominated boundary films—not from weaker hyaluronic acid anchoring, as previously thought.
The Illinois Grainger engineers are the first to use this powerful and versatile combination of techniques to visualize friction properties on soft interfaces in the context of osteoarthritis. Although AFM is widely recognized as a potent imaging tool for hard materials, the Illinois researchers’ work highlights its ability to concurrently capture the structures and friction properties of soft materials.
Beyond their pioneering methodology, the researchers’ work aims to advance discussion within their field by challenging the long-held belief that vesicles are superior lubricants. Conversely, their findings point to lamellar structures—favored by high-molecular weight hyaluronic acid—as a more durable and lower friction source of lubrication.
“That vesicles were held to be better lubricants is somewhat counterintuitive,” Rutland said. “I believe that we have now resolved this apparent paradox.”
The team is optimistic that their findings will have relevance beyond the lab and into a clinical setting.
“Our work provides a new perspective for guiding future osteoarthritis therapy,” Sun said. “We’ve reviewed the whole relationship between this lipid and hyaluronic acid complex microstructure: how they are related with their lubrication behaviors, and how osteoarthritis probably is promoted by the degradation of the molecular weight of hyaluronic acid. It could help prepare a future treatment that is more informed by science.”
Building on their initial findings, Espinosa Marzal’s group is already hard at work on their next goals: investigating potential synergistic effects between hyaluronic acid, phospholipids, and glycoproteins; creating a more complex model that better mimics the complexity of real articulation joints; and synthesizing new materials that could eventually replace cartilage or other soft tissues.
“We are going to the next level and saying, ‘What if we take another component: is there another mechanism from synergy of different components?’ Espinosa Marzal said. “Maybe it's not about the molecular weight of hyaluronic acid, but about other phospholipids or molecules that are present and play a different role.”
Illinois Grainger Engineering Affiliations
Rosa Espinosa Marzal is an Illinois Grainger Engineering professor in the Department of Materials Science and Engineering and the Department of Civil and Environmental Engineering. She is affiliated with the Materials Research Laboratory and the Institute for Genomic Biology. Espinosa Marzal holds the Ivan Racheff Professorship and the Donald Biggar Willett faculty scholar appointment.