Kilo-scale droplet generation in three-dimensional monolithic elastomer device (3D MED)

Abstract

Droplet-based microfluidics has led to transformational new approaches in diverse areas including materials synthesis and high-throughput biological assays. However, the translation of droplet microfluidics technology into commercial applications requires scale-up of droplet generation from the laboratory (<10 mL h(-1)) to the industrial (>1 L h(-1)) scale. To address this challenge, we develop a three-dimensional monolithic elastomer device (3D MED) for mass production of monodisperse emulsion droplets. Using double-sided imprinting, 3D microchannels are formed in a single elastomer piece that has 1000 parallel flow focusing generators (k-FFGs). Compared to previous work that parallelizes droplet generation, the 3D MED eliminates the needs for alignment and bonding of multiple pieces and thus makes it possible to achieve the high flow rates and pressure necessary for the kilo-scale generation of droplets. Using this approach, we demonstrate mass production of water-in-oil (W/O) emulsion droplets at production rates as high as 1.5 L h(-1) (>30 billion 45 μm diameter droplets per hour), with a coefficient of variation of droplet diameter of only 6.6%. Because of the simplicity, robustness, and manufacturability of our 3D MED architecture, it is well suited to bridge the gap between the continuously growing library of promising microfluidic technologies to generate microparticles that have been demonstrated in laboratory settings and their successful application in industry.

Liter-scale production of uniform gas bubbles via parallelization of flow-focusing generators

“…As described in our previous report, 26 we have developed a robust fabrication method for a three-dimensional monolithic elastomer device (3D MED) by eliminating the need for aligning and bonding multiple pieces of elastomer layers. A 3D MED with a three dimensional structure is fabricated by double-sided imprinting using a hard silicon master and a soft PDMS master.…”

“…By carefully designing the distribution network and tuning the channel resistances, it has been shown that up to 1,000 droplet generators can be integrated into a single microfluidic chip that has the production rate of several liters of liquid droplets per hour. 26 …”

Discovery in Droplets

“…(B) Through-hole-containing manifolds enable parallelization of a conventional droplet generation mode for unparalleled scales of production. Adapted from Jeong, H.-H.; Yelleswarapu, V. R.; Yadavali, S.; Issadore, D.; Lee, D. Lab Chip 2015 , Advance Article, DOI: 10.1039/C5LC01025J (ref 9) with permission of The Royal Society of Chemistry.…”

Parallel droplet microfluidics for high throughput cell encapsulation and synthetic microgel generation

“…However, coupled inlet and outlet flow paths present significant challenges to maintaining size control and low polydispersity of droplet diameter, due to propagation of pressure fluctuations between nozzles. Nonetheless, uniform droplet production has been shown on parallel droplet generators with a variety of configurations [30][31][32][33][34] . Parallel microfluidics have been used to produce microgels through light-initiated free-radical polymerization on single layer microfluidics, and the nature of crosstalk between parallel droplet generators has been studied in this context 35 .…”