Williams P F, Powell G L, LaBerge M
Department of Bioengineering, Clemson University, South Carolina.
Proc Inst Mech Eng H. 1993;207(1):59-66. doi: 10.1243/PIME_PROC_1993_207_268_02.
Dipalmitoyl phosphatidylcholine (DPPC), the major lipidic component of the synovial fluid (45 per cent), has been implicated in previous studies in synovial joint lubrication as a potential boundary lubricant for articular cartilage. The purpose of this study was to evaluate the effectiveness of DPPC as a boundary lubricant at physiological stresses experienced by weight-bearing joints (up to 7.5 MPa). The sliding coefficients of static and kinetic friction for glass surfaces coated with DPPC layers of physiological thickness (70 nm) were measured as a function of average contact stress, contact geometry (point and line), applied load and relative velocity (from 25 to 0 mm/s) and compared to the coefficient of friction for clean glass in the same conditions. The coefficient of friction for DPPC-lubricated surfaces was dependent on contact geometry, obeyed Amonton's law (not dependent on axial load or contact area), was dependent on relative velocity within the range stated and was an effective lubricant at physiological stresses. This study showed that dipalmitoyl phosphatidylcholine can be an effective boundary lubricant at stresses observed in load-bearing joints. Because of their surface-active nature, these adsorbed molecules might also act as a protective layer for the articular surfaces.
二棕榈酰磷脂酰胆碱（DPPC）是滑液的主要脂质成分（占45%），在先前的研究中，它被认为是滑膜关节润滑中关节软骨潜在的边界润滑剂。本研究的目的是评估DPPC在负重关节所承受的生理应力（高达7.5兆帕）下作为边界润滑剂的有效性。测量了涂有生理厚度（70纳米）DPPC层的玻璃表面的静摩擦系数和动摩擦系数，作为平均接触应力、接触几何形状（点接触和线接触）、施加负载和相对速度（25至0毫米/秒）的函数，并与相同条件下清洁玻璃的摩擦系数进行比较。DPPC润滑表面的摩擦系数取决于接触几何形状，符合阿蒙顿定律（不取决于轴向载荷或接触面积），在所述速度范围内取决于相对速度，并且在生理应力下是一种有效的润滑剂。本研究表明，二棕榈酰磷脂酰胆碱在负重关节所观察到的应力下可以是一种有效的边界润滑剂。由于其表面活性性质，这些吸附分子也可能作为关节表面的保护层。
