Detection and sizing of single droplets flowing in a lab-on-a-chip device by measuring impedance fluctuations

SENSORS AND ACTUATORS B-CHEMICAL

卷:236

Article

Yakdi, Nour Eddin¹  Huet, Francois¹  Ngo, Kieu¹ 

[1] Univ Paris 06, CNRS, Sorbonne Univ, LISE, F-75005 Paris, France

关键词: Particle sizing techniques;    Twophase systems;    Electrochemical noise;    Impedance;    Electrolyte resistance;    Microfluidic device;    Oil droplet;   

DOI  :  10.1016/j.snb.2016.05.123

来源: Elsevier

【 摘 要 】

This paper is devoted to the evaluation of the electrochemical noise technique consisting in measuring the fluctuations of the electrolyte resistance (ER) between two metallic electrodes immerged in a conductive electrolyte to detect and characterize single particles circulating in a microfluidic device, without the help of optical measurements that require good visibility of the detection region. Numerical simulations were performed with the finite element method to study the influence of the dimensions of the channel and the electrodes on the ER. Measurements of the ER variations due to the passage of oil droplets and plugs passing between the electrodes were carried out. Excellent agreement was obtained between the theoretical and experimental ER transients, which allowed the velocity and diameter of the oil droplets to be estimated with an accuracy of a few percents in the case of droplet diameters ranging from 60 to 100 mu m. According to the numerical simulations and the amplitude of the background noise, oil droplets of diameter larger than 20-25 mu m can be detected in the microchannel used (cross section of 100 mu m x 100 mu m and 100 mu m x 100 mu m electrodes separated by a gap of 100 mu m). Developments of smaller microfluidic devices are under progress to detect and characterize particles of a few micrometers, such as biological cells for example. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free