Negative Pressure Provides Simple and Stable Droplet Generation in a Flow-Focusing Microfluidic Device

Micromachines

Anatoly A. Evstrapov¹  Anton S. Bukatin²  Nikita A. Filatov² 

[1] Laboratory of Bio and Chemosensor Microsystems, Institute for Analytical Instrumentation of RAS, 198095 Saint-Petersburg, Russia;Laboratory of Renewable Energy Sources, Alferov Saint Petersburg National Research Academic University of the Russian Academy of Sciences, 194021 Saint Petersburg, Russia;

关键词: droplet microfluidics;    flow focusing;    water-in-oil droplets;    negative pressure;    emulsion;   

DOI  :  10.3390/mi12060662

来源: DOAJ

【 摘 要 】

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.

【 授权许可】

Unknown