Izon Science Limited, 8C Homersham Place, P.O. Box 39168, Burnside, Christchurch 8053, New Zealand.
School of Mathematics and Physics, The University of Queensland , Brisbane 4072, Australia.
Anal Chem. 2016 Sep 6;88(17):8648-56. doi: 10.1021/acs.analchem.6b01818. Epub 2016 Aug 10.
The use of resistive pulse sensors for submicron particle size measurements relies on a clear understanding of pulse size distributions. Here, broadening of such distributions has been studied and explained using conical pores and nominally monodisperse polystyrene particles 200-800 nm in diameter. The use of tunable resistive pulse sensing (TRPS) enabled continuous in situ control of the pore size during experiments. Pulse size distributions became broader when the pore size was increased and featured two distinct peaks. Similar distributions were generated using finite element simulations, which suggested that relatively large pulses are produced by particles with trajectories passing near to the edge of the pore. Other experiments determined that pulse size distributions are independent of applied voltage but broaden with increasing pressure applied across the membrane. The applied pressure could also be reversed in response to a pulse, which enabled repeated measurement of individual particles moving back and forth through the pore. Hydrodynamic and electrophoretic focusing each appear to affect particle trajectories under certain conditions.
使用电阻脉冲传感器进行亚微米颗粒尺寸测量需要清晰地了解脉冲尺寸分布。在这里，使用锥形孔和标称单分散聚苯乙烯颗粒（直径 200-800nm）研究并解释了这种分布的展宽。可调电阻脉冲传感（TRPS）的使用使得在实验过程中能够连续原位控制孔径。当孔径增加且具有两个明显的峰值时，脉冲尺寸分布变得更宽。使用有限元模拟生成了类似的分布，这表明轨迹接近孔边缘的颗粒会产生相对较大的脉冲。其他实验确定，脉冲尺寸分布与施加的电压无关，但随着跨膜施加的压力增加而变宽。施加的压力也可以响应脉冲而反向，从而能够重复测量单个颗粒在孔中来回移动。在某些条件下，流体动力学和电泳聚焦似乎都会影响颗粒轨迹。
