Lubricating nano/micro particles for osteoarthritis therapy

Osteoarthritis (OA) is a prevalent joint disorder characterized by cartilage degeneration and synovial lubrication failure, resulting in pain and restricted movement. From a physiological standpoint, key macromolecules in synovial fluid, such as hyaluronic acid, phospholipids, and lubricin, play essential roles in maintaining the boundary lubrication of articular cartilage. In OA, however, cartilage damage induces inflammatory responses that alter the composition of synovial fluid, thereby compromising its lubricating function. This results in increased friction at the joint interface, which not only exacerbates cartilage degradation but also amplifies local inflammatory reactions. Therefore, restoring effective cartilage lubrication is critical for successful OA treatment. This review elucidates the pathological mechanisms underlying lubrication failure in OA and assesses current clinical interventions, with a specific focus on natural biological lubricants. Furthermore, we elaborate on recent advancements in the development of lubricating nano/micro particles, emphasizing the significance of material selection, particle type, size, shape, surface modification, and the integration of drug delivery strategies to enhance their performance in joint environments. This review aims to offer novel perspectives for future OA treatment approaches, particularly regarding the rational design and application of lubricating nano/micro particles in OA therapy.