Piao Linfeng, Park Hyungmin, Jo Chris Hyunchul
Department of Mechanical & Aerospace Enginnering, Seoul National University, Seoul, Korea.
Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea.
PLoS One. 2017 Nov 2;12(11):e0187509. doi: 10.1371/journal.pone.0187509. eCollection 2017.
In the present study, we propose a theoretical framework to predict the recovery rates of platelets and white blood cells in the process of centrifugal separation of whole blood contained in a tube for the preparation of platelet-rich plasma. Compared to previous efforts to optimize or standardize the protocols of centrifugation, we try to further the physical background (i.e., based on the multiphase flow phenomena) of analysis to develop a universal approach that can be applied to widely different conditions. That is, one-dimensional quasi-linear partial differential equation to describe the centrifugal sedimentation of dispersed phase (red and white blood cells) in continuous phase (plasma) is derived based on the kinematic-wave theory. With the information of whole blood volume and tube geometry considered, it is possible to determine the positions of interfaces between supernatant/suspension and suspension/sediment, i.e., the particle concentration gradient in a tube, for a wide range of centrifugation parameters (time and acceleration). While establishing a theory to predict the recovery rates of the platelet and white blood cell from the pre-determined interface positions, we also propose a new correlation model between the recovery rates of plasma and platelets, which is found to be a function of the whole blood volume, centrifugal time and acceleration, and tube geometry. The present predictions for optimal condition show good agreements with available human clinical data, obtained from different conditions, indicating the universal applicability of our method. Furthermore, the dependence of recovery rates on centrifugal conditions reveals that there exist a different critical acceleration and time for the maximum recovery rate of platelets and white blood cells, respectively. The other parameters such as hematocrit, whole blood volume and tube geometry are also found to strongly affect the maximum recovery rates of blood cells, and finally, as a strategy for increasing the efficiency, we suggest to dilute the whole blood, increase the whole blood volume with a tube geometry fixed.
在本研究中，我们提出了一个理论框架，用于预测在制备富含血小板血浆的过程中，对管中全血进行离心分离时血小板和白细胞的回收率。与以往优化或标准化离心方案的努力相比，我们试图进一步深入分析的物理背景（即基于多相流现象），以开发一种可应用于广泛不同条件的通用方法。也就是说，基于运动波理论推导了一维拟线性偏微分方程，以描述连续相（血浆）中分散相（红细胞和白细胞）的离心沉降。考虑到全血体积和管几何形状的信息，对于广泛的离心参数（时间和加速度），可以确定上清液/悬浮液和悬浮液/沉淀物之间界面的位置，即管中的颗粒浓度梯度。在建立从预先确定的界面位置预测血小板和白细胞回收率的理论时，我们还提出了血浆和血小板回收率之间的新关联模型，发现它是全血体积、离心时间和加速度以及管几何形状的函数。当前对最佳条件的预测与从不同条件获得的现有人类临床数据显示出良好的一致性，表明我们方法的普遍适用性。此外，回收率对离心条件的依赖性表明，血小板和白细胞的最大回收率分别存在不同的临界加速度和时间。还发现诸如血细胞比容、全血体积和管几何形状等其他参数对血细胞的最大回收率有强烈影响，最后，作为提高效率的策略，我们建议稀释全血，在管几何形状固定的情况下增加全血体积。
