Parallelized edge-based droplet generation (EDGE) devices

Abstract

We here report on three parallelized designs of the new edge-based droplet generation mechanism, which, unlike existing mechanisms, produces many equally sized droplets simultaneously at a single droplet formation unit. Operation of the scaled-out systems is straight forward; only the oil inlet pressure has to be controlled to let all the units produce oil droplets, given certain basic design constraints. For systems with a typical nozzle depth of 1.2 microm, the mean droplet diameter is 7.5 microm and the coefficient of variation is below 10%. The number of droplets that is formed per unit can easily be increased by increasing the length of the unit. The stable pressure range in which monodisperse droplets are formed can be extended by small adjustments to the design. Overall, the EDGE devices are simple in design and robust in use, making them suitable for massive outscaling.

Parallel generation of uniform fine droplets at hundreds of kilohertz in a flow-focusing module

“…Although these devices can produce a good measure of fine droplets, shear-based techniques such as flow-focusing generate a more monodisperse product, at a higher generation rate per formation unit. 1,11,21 As well, the membrane structure of MCE chips does not favor the preparation of complex droplets with controlled composition, 15 and the product quickly becomes polydisperse above a critical working range of the dispersed phase flow. 18,21 Despite being an area of active research, shear-based microfluidic scale-up lacks a system capable of competing with MCE chips in generating, in mass amount, droplets of diameter $10 lm or less.…”

“…1,11,21 As well, the membrane structure of MCE chips does not favor the preparation of complex droplets with controlled composition, 15 and the product quickly becomes polydisperse above a critical working range of the dispersed phase flow. 18,21 Despite being an area of active research, shear-based microfluidic scale-up lacks a system capable of competing with MCE chips in generating, in mass amount, droplets of diameter $10 lm or less. To be practical for applications requiring fine droplets, and in particular for clinical applications requiring many millions of droplets for intravenous or intra-arterial administration, parallel systems must be designed not with a mind for volumetric throughput, but instead for minimum droplet size and maximizing the generation frequency.…”

“…19 More recently, Kobayashi et al 20 presented a 60 Â 60-mm MCE chip made of single-crystal silicon, containing 14 microchannel arrays and 1.2 Â 10 4 microchannels, for mass-producing uniform fine droplets of soybean oil; throughput reached 1.5 ml h À1 , with an average droplet diameter of 10 lm. Similarly, van Dijke et al 21 reported on three parallelized designs of the edge-based droplet generation mechanism; formation of 7.5 lm droplets, which occurs spontaneously along a shallow, very wide slit, reached an estimated 250 droplets per 100 lm plateau length, with a CV below 10%. Although these devices can produce a good measure of fine droplets, shear-based techniques such as flow-focusing generate a more monodisperse product, at a higher generation rate per formation unit.…”

Industrial lab-on-a-chip: Design, applications and scale-up for drug discovery and delivery

“…forcing the continuous phase to flow through a narrow gap between the interface and the orifice 21 wall. To maintain the applied flow rate, a higher upstream pressure is needed in the continuous 22 phase stream, which leads to pinching of the interface.…”

“…The mold is then pressed into a softened polymer to 20 force it to flow into the cavities of the mold. Once the polymer has conformed to the shape of the 21 stamp, it is cooled to a temperature below the glass transition temperature so that it is sufficiently 22 hard to be separated from the mold. Finally, a transparent cover plate must be bonded to the 23 PMMA substrate.…”