Frank R S, Tsai M A
Department of Mechanical Engineering, University of Rochester, NY 14627.
J Biomech Eng. 1990 Aug;112(3):277-82. doi: 10.1115/1.2891185.
The passage times of individual human neutrophils through single capillary-sized pores in polycarbonate membranes were measured with the resistive pulse technique, and results were compared to those obtained from the micropipette aspiration of entire cells. Pore transit measurement serves as a useful means to screen populations of cells, and allows for protocols that measure time dependent changes to the population. Neutrophils exhibited a highly linear pressure/flow rate relationship at aspiration pressures from 200 Pa to 1,500 Pa in both the pore and pipette systems. Cellular viscosity, as determined by the method of Hochmuth and Needham, was 89.0 Pa.s for the pore systems and 134.9 Pa.s for the pipette systems. These results are in general agreement with recent values of neutrophil viscosity published in the literature. Extrapolation of the observed linear flow response revealed an apparent minimum pressure for whole cell aspiration significantly above the threshold pressure predicted by Evans' liquid drop model. However, whole cell aspiration was achieved in both the pore and pipette systems at pressures below this extrapolated minimum, although the calculated cellular viscosity was greatly increased. The implications of these two regimes of cell deformation is unclear. This behavior could be explained by shear thinning of the material in the cell body. However the origin of this phenomenon may be in the cortical region of the cell, which exhibits an elastic tension that may be deformation rate dependent.
采用电阻脉冲技术测量了单个人类中性粒细胞通过聚碳酸酯膜中单个毛细血管大小孔隙的通过时间，并将结果与通过对整个细胞进行微量吸管抽吸获得的结果进行了比较。孔隙通过测量是筛选细胞群体的一种有用方法，并允许采用测量群体随时间变化的方案。在孔隙系统和吸管系统中，中性粒细胞在200帕至1500帕的抽吸压力下均表现出高度线性的压力/流速关系。根据霍赫穆特和尼德姆的方法测定，孔隙系统的细胞粘度为89.0帕·秒，吸管系统的细胞粘度为134.9帕·秒。这些结果与文献中最近公布的中性粒细胞粘度值总体一致。对观察到的线性流动响应进行外推，结果显示全细胞抽吸的表观最小压力明显高于埃文斯液滴模型预测的阈值压力。然而，在孔隙系统和吸管系统中，在低于该外推最小值的压力下均实现了全细胞抽吸，尽管计算出的细胞粘度大大增加。这两种细胞变形状态的含义尚不清楚。这种行为可以用细胞体内物质的剪切稀化来解释。然而，这种现象的起源可能在于细胞的皮质区域，该区域表现出可能与变形速率相关的弹性张力。
