Electrical cell counting process characterization in a microfluidic impedance cytometer
Electrical cell counting process characterization in a microfluidic impedance cytometer
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DOI：
10.1007/s10544-014-9874-0
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发表时间：
2014-10-01
影响因子：
2.8
通讯作者：
Bashir, Rashid
中科院分区：
文献类型：
--
作者：
Hassan, Umer;Bashir, Rashid
基于库尔特原理的微流控粒子计数在卫生和医学领域有着广泛的应用。使用微流控粒子计数器进行细胞计数速度快，需要的样品量小，目前正用于人类和动物的疾病诊断。细胞计数过程的完整表征对于精确的细胞计数至关重要，特别是在微流控装置中具有异质群体样品与不同试剂相互作用的复杂系统中。在本文中，我们描述了使用微流控阻抗细胞仪的电细胞计数过程。红细胞在芯片上从全血中裂解，裂解被淬灭以保存白细胞，白细胞随后通过一个15 μ m × 15 μ m的测量通道，用于电计数细胞。我们发现细胞计数随时间的变化是非均匀的泊松过程，细胞计数随时间的变化呈对数正态分布，其偏态可归因于用于测量血液的缓冲液中细胞的扩散。我们进一步发现异质细胞群（即不同类型的细胞）根据细胞大小表现出不同的扩散特性。与粒细胞和单核细胞相比，淋巴细胞在空间上弥漫性更强。细胞出现之间的时间差遵循指数分布，并且随时间绘制时验证细胞扩散特性。我们还利用泊松计数统计描述了在指定时间间隔内计数器上出现多个细胞的概率。对于高细胞浓度的样品，我们还根据我们的颗粒计数特性推导出所需的样品稀释度。通过考虑基于粒度的颗粒扩散和估计所需稀释度来表征缓冲液是准确计数结果的关键参数。
Particle counting in microfluidic devices with coulter principle finds many applications in health and medicine. Cell enumeration using microfluidic particle counters is fast and requires small volumes of sample, and is being used for disease diagnostics in humans and animals. A complete characterization of the cell counting process is critical for accurate cell counting especially in complex systems with samples of heterogeneous population interacting with different reagents in a microfluidic device. In this paper, we have characterized the electrical cell counting process using a microfluidic impedance cytometer. Erythrocytes were lysed on-chip from whole blood and the lysing was quenched to preserve leukocytes which subsequently pass through a 15 mu m x 15 mu m measurement channel used to electrically count the cells. We show that cell counting over time is a non-homogeneous Poisson process and that the electrical cell counts over time show the log-normal distribution, whose skewness can be attributed to diffusion of cells in the buffer that is used to meter the blood. We further found that the heterogeneous cell population (i.e. different cell types) shows different diffusion characteristics based on the cell size. Lymphocytes spatially diffuse more as compared to granulocytes and monocytes. The time difference between the cell occurrences follows an exponential distribution and when plotted over time verifies the cell diffusion characteristics. We also characterized the probability of occurrence of more than one cell at the counter within specified time intervals using Poisson counting statistics. For high cell concentration samples, we also derived the required sample dilution based on our particle counting characterization. Buffer characterization by considering the size based particle diffusion and estimating the required dilution are critical parameters for accurate counting results.