Interactions between molecules in the synovial fluid and the cartilage surface may play a vital role in the formation of adsorbed films that contribute to the low friction of cartilage boundary lubrication. Osteoarthritis (OA) is the most common degenerative joint disease. Previous studies have shown that in OA-diseased joints, hyaluronan (HA) not only breaks down resulting in a much lower molecular weight (MW), but also its concentration is reduced ten times. Here, we have investigated the structural changes of lipid-HA complexes as a function of HA concentration and MW to simulate the physiologically relevant conditions that exist in healthy and diseased joints. Small angle neutron scattering and dynamic light scattering were used to determine the structure of HA-lipid vesicles in bulk solution, while a combination of atomic force microscopy and quartz crystal microbalance was applied to study their assembly on a gold surface. We infer a significant influence of both MW and HA concentrations on the structure of HA-lipid complexes in bulk and assembled on a gold surface. Our results suggest that low MW HA cannot form an amorphous layer on the gold surface, which is expected to negatively impact the mechanical integrity and longevity of the boundary layer and could contribute to the increased wear of the cartilage that has been reported in joints diseased with OA.

中文翻译：

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深入了解骨关节炎病症中脂质-乙酰透明质酸复合物的组装。

滑液中分子与软骨表面之间的相互作用可能在吸附膜的形成中起着至关重要的作用，吸附膜有助于软骨边界润滑的低摩擦。骨关节炎（OA）是最常见的退行性关节疾病。先前的研究表明，在患有 OA 疾病的关节中，透明质酸 (HA) 不仅会分解导致分子量 (MW) 大大降低，而且其浓度也会降低十倍。在这里，我们研究了脂质-HA 复合物的结构变化作为 HA 浓度和 MW 的函数，以模拟健康和患病关节中存在的生理相关条件。小角度中子散射和动态光散射用于确定本体溶液中 HA 脂质囊泡的结构，同时结合使用原子力显微镜和石英晶体微天平来研究它们在金表面上的组装。我们推断 MW 和 HA 浓度对散装和组装在金表面上的 HA-脂质复合物结构的显着影响。我们的结果表明，低 MW HA 不能在金表面形成无定形层，这预计会对边界层的机械完整性和寿命产生负面影响，并可能导致关节磨损增加办公自动化。