Glycosaminoglycans and glycoproteins influence the elastic response of synovial fluid nanofilms on model oxide surfaces
Glycosaminoglycans and glycoproteins influence the elastic response of synovial fluid nanofilms on model oxide surfaces
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DOI：
10.1016/j.colsurfb.2022.112407
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发表时间：
2022-02-15
影响因子：
5.8
通讯作者：
Eguiluz，Roberto C. Andresen
中科院分区：
文献类型：
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作者：
Mann，Amar S.;Smith，Ariell M.;Eguiluz，Roberto C. Andresen
滑液（SF）是在关节中发现的天然润滑剂，在限制和相对运动下提供独特的软骨表面保护膜。虽然已知大分子成分的协同相互作用提供了其独特的承载和摩擦学性能，但尚不完全了解两种主要成分，糖胺聚糖（GAG）和糖蛋白，如何调节坚固的承载膜的形成和力学。在这里，我们提出的证据表明，承载能力，而不是摩擦学性能，所形成的SF膜强烈依赖于其组件的完整性。为此目的，我们使用酶处理、具有耗散的石英晶体微天平（QCM-D）和表面力装置（SFA）的组合来表征SF膜在模型氧化物上的形成和承载能力（即，硅酸盐）表面。我们发现，蛋白质裂解后，薄膜的弹性降低，裂解GAG导致不可逆的（塑料）分子重排的薄膜成分时，受到限制。了解SF的薄膜力学可以深入了解疾病的进展，如关节炎，但也可能适用于开发新的植入物表面处理或新的仿生润滑剂。
Synovial fluid (SF) is the natural lubricant found in articulated joints, providing unique cartilage surface protecting films under confinement and relative motion. While it is known that the synergistic interactions of the macromolecular constituents provide its unique load-bearing and tribological performance, it is not fully understood how two of the main constituents, glycosaminoglycans (GAGs) and glycoproteins, regulate the formation and mechanics of robust load-bearing films. Here, we present evidence that the load-bearing capabilities, rather than the tribological performance, of the formed SF films depend strongly on its components' integrity. For this purpose, we used a combination of enzymatic treatments, quartz crystal microbalance with dissipation (QCM-D), and the surface forces apparatus (SFA) to characterize the formation and load-bearing capabilities of SF films on model oxide (i.e., silicates) surfaces. We find that, upon cleavage of proteins, the elasticity of the films is reduced and that cleaving GAGs results in irreversible (plastic) molecular re-arrangements of the film constituents when subjected to confinement. Understanding thin film mechanics of SF can provide insight into the progression of diseases, such as arthritis, but may also be applicable to the development of new implant surface treatments or new biomimetic lubricants.