Stauber Hagit, Waisman Dan, Korin Netanel, Sznitman Josué
Department of Biomedical Engineering, Technion - Israel Institute of Technology, 3200003 Haifa, Israel.
Department of Neonatology, Carmel Medical Center, 3436212 Haifa, Israel; Faculty of Medicine, Technion - Israel Institute of Technology, 3200003 Haifa, Israel.
Med Eng Phys. 2017 Oct;48:49-54. doi: 10.1016/j.medengphy.2017.08.006. Epub 2017 Aug 23.
Microfluidic-based assays have become increasingly popular to explore microcirculation in vitro. In these experiments, blood is resuspended to a desired haematocrit level in a buffer solution, where frequent choices for preparing RBC suspensions comprise notably Dextran and physiological buffer. Yet, the rational for selecting one buffer versus another is often ill-defined and lacks detailed quantification, including ensuing changes in RBC flow characteristics. Here, we revisit RBC suspensions in microflows and attempt to quantify systematically some of the differences emanating between buffers. We measure bulk flow rate (Q) of RBC suspensions, using PBS- and Dextran-40, as a function of the applied pressure drop (ΔP) for two hematocrits (∼0% and 23%). Two distinct microfluidic designs of varying dimensions are employed: a straight channel larger than and a network array similar to the size of individual RBCs. Using the resulting pressure-flow curves, we extract the equivalent hydrodynamic resistances and estimate the relative viscosities. These efforts are a first step in rigorously quantifying the influence of the 'background' buffer on RBC flows within microfluidic devices and thereby underline the importance of purposefully selecting buffer suspensions for microfluidic in vitro assays.
基于微流控的分析方法在体外探索微循环方面越来越受欢迎。在这些实验中，血液在缓冲溶液中重悬至所需的血细胞比容水平，制备红细胞悬浮液时常用的选择包括右旋糖酐和生理缓冲液。然而，选择一种缓冲液而非另一种缓冲液的理由往往不明确且缺乏详细的量化，包括随之而来的红细胞流动特性变化。在这里，我们重新审视微流中的红细胞悬浮液，并试图系统地量化不同缓冲液之间产生的一些差异。我们测量了使用 PBS 和 Dextran - 40 的红细胞悬浮液的总体流速（Q），作为两种血细胞比容（约 0% 和 23%）下施加压降（ΔP）的函数。采用了两种不同尺寸的微流控设计：一种是比单个红细胞大的直通道，另一种是类似于单个红细胞大小的网络阵列。利用所得的压力 - 流量曲线，我们提取了等效流体动力阻力并估计了相对粘度。这些工作是严格量化“背景”缓冲液对微流控装置内红细胞流动影响的第一步，从而强调了为微流控体外分析有目的地选择缓冲液悬浮液的重要性。
