J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL 32610.
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32610.
J Biomech Eng. 2022 Aug 1;144(8). doi: 10.1115/1.4053794.
Changes in synovial fluid viscosity may be used to detect joint disease; however, methods to evaluate these changes at the point-of-care are currently rudimentary. Previously, we demonstrated that magnetic particle translation through static synovial fluid could serve as a surrogate marker of synovial fluid mechanics. In this work, we examine the magnetic deflection of a stream of particles flowing through a stream of synovial fluid and relate this deflection to changes in fluid mechanics. First, a flow device was designed, where a stream of magnetic particles flows along with synovial fluid. As the particle stream approaches and passes a fixed permanent magnet, the particle stream deflects. Conceptually, as the synovial fluid viscosity decreases, the deflection of the particle stream should increase due to a decreased drag force opposing the force magnetization. To assess this concept, particle deflection was first measured in Newtonian glycerol solutions of known varying viscosity under different flow conditions. Next, the device was used to test bovine synovial fluid viscosity, which had been progressively degraded using ultrasonication. A strong correlation was observed between the deflection of the magnetic particles and the viscosity of the glycerol solutions (R2 = 0.987) and the amount of ultrasonic degradation of synovial fluid (R2 = 0.7045). In the future, the principle of particle deflection may be used to design point-of-care quantification of synovial fluid mechanics, as the assessment does not require particles to be separated from the fluid for quantification and could be conducted under simple flow conditions.
滑液黏度的变化可用于检测关节疾病；然而，目前在即时护理点评估这些变化的方法还很基础。此前，我们证明了通过静态滑液的磁性粒子平移可以作为滑液力学的替代标志物。在这项工作中，我们研究了通过滑液流的粒子流的磁偏转，并将这种偏转与流体力学的变化联系起来。首先，设计了一种流动装置，其中磁粒子流与滑液一起流动。当粒子流接近并通过固定的永磁体时，粒子流会发生偏转。从概念上讲，由于滑膜液的粘度降低，阻力减小，抵抗磁化力的阻力减小，因此粒子流的偏转应该增加。为了评估这一概念，首先在不同的流动条件下测量了已知粘度不断变化的牛顿甘油溶液中粒子的偏转。接下来，该装置用于测试牛的滑液粘度，该滑液已通过超声处理逐步降解。观察到磁性粒子的偏转与甘油溶液的粘度之间存在很强的相关性（R2=0.987），以及滑液超声降解的程度之间存在很强的相关性（R2=0.7045）。将来，粒子偏转的原理可用于设计即时护理点滑液力学的定量分析，因为评估不需要将粒子从流体中分离出来进行定量分析，并且可以在简单的流动条件下进行。
