Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Talanta. 2018 Jul 1;184:418-428. doi: 10.1016/j.talanta.2018.03.023. Epub 2018 Mar 15.
The resistive pulse sensing (RPS) method has been widely used for characterization of particles, cells, and biomolecules due to its merits of high sensitivity and resolution. This paper investigates working parameters involved in detecting submicron and micron-sized particles by the differential RPS method on microfluidic chips. Effects of particle-to-sensor size ratio, ionic concentration and pH of the electrolyte solution, and applied electric field are studied systematically by using polystyrene particles with a size range from 140 nm to 5 µm. The results show that both the amplitude and the signal-to-noise ratio (SNR) of the RPS signals increase with the particle-to-sensor size ratio as well as the ionic concentration of the electrolyte media. The amplitude of the RPS signals also increases with increasing applied voltage, while the SNR experiences an upslope at low voltages and a decline under the condition of high voltages. pH has little effect on the background noise of the differential RPS signals but reduces the amplitude of the RPS signals at high pH. Grouping of RPS signals is considered to be caused by interactions between the sensor walls and the particles. Nanoparticle detection by the differential RPS method can be enhanced by optimizing these working parameters.
电阻脉冲感应（RPS）方法由于其灵敏度和分辨率高的优点，已被广泛用于颗粒、细胞和生物分子的特性描述。本文研究了在微流控芯片上通过差分 RPS 方法检测亚微米和微米级颗粒时涉及的工作参数。通过使用尺寸范围为 140nm 至 5μm 的聚苯乙烯颗粒，系统研究了颗粒与传感器尺寸比、电解质溶液的离子浓度和 pH 值以及外加电场的影响。结果表明，RPS 信号的幅度和信噪比（SNR）都随着颗粒与传感器尺寸比以及电解质介质的离子浓度的增加而增加。RPS 信号的幅度也随着外加电压的增加而增加，而 SNR 在低电压下呈上升趋势，在高电压下则下降。pH 值对差分 RPS 信号的背景噪声影响不大，但会降低高 pH 值下的 RPS 信号幅度。RPS 信号的分组被认为是由传感器壁与颗粒之间的相互作用引起的。通过优化这些工作参数，可以增强差分 RPS 方法对纳米颗粒的检测。
