Bento David, Lopes Sara, Maia Inês, Lima Rui, Miranda João M
CEFT, Faculdade de Engenharia da Universidade do Porto (FEUP) Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Polytechnic Institute of Bragança, ESTiG/IPB, C. Sta. Apolónia, 5300-857 Bragança, Portugal.
Micromachines (Basel). 2020 Mar 26;11(4):344. doi: 10.3390/mi11040344.
Air inside of blood vessels is a phenomenon known as gas embolism. During the past years, studies have been performed to assess the influence of air bubbles in microcirculation. In this study, we investigated the flow of bubbles in a microchannel network with several bifurcations, mimicking part of a capillary system. Thus, two working fluids were used, composed by sheep red blood cells (RBCs) suspended in a Dextran 40 solution with different hematocrits (5% and 10%). The experiments were carried out in a polydimethylsiloxane (PDMS) microchannel network fabricated by a soft lithography. A high-speed video microscopy system was used to obtain the results for a blood flow rate of 10 µL/min. This system enables the visualization of bubble formation and flow along the network. The results showed that the passage of air bubbles strongly influences the cell's local concentration, since a higher concentration of cells was observed upstream of the bubble, whereas a lower local hematocrit was visualized at the region downstream of the bubble. In bifurcations, bubbles may split asymmetrically, leading to an uneven distribution of RBCs between the outflow branches.
血管内出现空气是一种被称为气体栓塞的现象。在过去几年中，已经开展了多项研究来评估气泡在微循环中的影响。在本研究中，我们在一个具有多个分支的微通道网络中研究了气泡的流动情况，该网络模拟了部分毛细血管系统。因此，使用了两种工作流体，它们由悬浮在不同血细胞比容（5%和10%）的右旋糖酐40溶液中的绵羊红细胞（RBC）组成。实验在通过软光刻制造的聚二甲基硅氧烷（PDMS）微通道网络中进行。使用高速视频显微镜系统获取了血流速率为10微升/分钟时的结果。该系统能够可视化气泡的形成以及沿网络的流动情况。结果表明，气泡的通过对细胞的局部浓度有强烈影响，因为在气泡上游观察到细胞浓度较高，而在气泡下游区域则观察到局部血细胞比容较低。在分支处，气泡可能会不对称分裂，导致流出分支之间红细胞分布不均。
