Red blood cell fatigue evaluation based on the close-encountering point between extensibility and recoverability
Red blood cell fatigue evaluation based on the close-encountering point between extensibility and recoverability
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DOI：
10.1039/c3lc51003d
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发表时间：
2014-01-01
期刊：
影响因子：
6.1
通讯作者：
Kaneko, Makoto
中科院分区：
文献类型：
--
作者：
Sakuma, Shinya;Kuroda, Keisuke;Kaneko, Makoto
红细胞（RBC）在人的一生中要在人体循环几十万次。因此，它们的变形能力是非常重要的，特别是当它们通过一个直径可窄至3 μ m的局部毛细血管时。虽然已经有许多作品讨论了模拟毛细血管（如微通道）的变形能力，但就我们所研究的文献而言，迄今为止还没有关于往复机械应力后形状变化的工作报道。其中一个原因是没有适当的实验系统来实现这样的测试。本文提出了红细胞疲劳评价的新概念。疲劳状态的定义是当材料的可拓性和可恢复性特性同时满足时，往复机械应力作用的时间。我们面临的挑战是如何构建一个能够在微通道中实现红细胞稳定和精确控制的系统。为此，我们新引入了两个基本组件。一种是机器人泵，能够在平衡状态下以+/- 0.24 μ m的精度操纵细胞，最大响应时间为15 ms。另一种是在线高速摄像机，能够以1khz的采样率跟踪红细胞的位置。通过利用这些组件，我们可以在1000倍的往复机械应力下连续观察RBC的长度。通过这些实验，我们发现导致疲劳状态的重复次数与可拓性密切相关。
Red blood cells (RBC) circulate the human body several hundred thousand times in their life span. Therefore, their deformability is really important, especially when they pass through a local capillary whose diameter can be as narrow as 3 mu m. While there have been a number of works discussing the deformability in a simulated capillary such as a microchannel, as far as we examined in the literature, no work focusing on the change of shape after reciprocated mechanical stress has been reported so far. One of the reasons is that there have been no appropriate experimental systems to achieve such a test. This paper presents a new concept of RBC fatigue evaluation. The fatigue state is defined by the time of reciprocated mechanical stress when the extensibility and the recoverability characteristics meet each other. Our challenge is how to construct a system capable of achieving stable and accurate control of RBCs in a microchannel. For this purpose, we newly introduced two fundamental components. One is a robotic pump capable of manipulating a cell in the accuracy of +/- 0.24 mu m in an equilibrium state with a maximum response time of 15 ms. The other is an online high speed camera capable of chasing the position of RBCs with a sampling rate of 1 kHz. By utilizing these components, we could achieve continuous observation of the length of a RBC over a 1000 times reciprocated mechanical stress. Through these experiments, we found that the repeat number that results in the fatigue state has a close correlation with extensibility.