A 3D printed size-tunable flow-focusing droplet microdevice to produce cell-laden hydrogel microspheres

AbstractMost commercial microfluidic droplet generators rely on the planar flow-focusing configuration implemented in polymer or glass chips. The planar geometry, however, suffers from many limitations and drawbacks, such as the need of specific coatings or the use of dedicated surfactants, depending on the fluids in play. On the contrary, and thanks to their axisymmetric geometry, glass capillary-based droplet generators are a priori not fluid-dependent. Nevertheless, they have never reached the market because their assembly requires fastidious and not scalable fabrication techniques. Here we present a new device, called Raydrop, based on the alignment of two capillaries immersed in a pressurized chamber containing the continuous phase. The dispersed phase exits one of the capillaries through a 3D-printed nozzle placed in front of the extraction capillary for collecting the droplets. This non-embedded implementation of an axisymmetric flow-focusing is referred to non-embedded co-flow-focusing configuration. Experimental results demonstrate the universality of the device in terms of the variety of fluids that can be emulsified, as well as the range of droplet radii that can be obtained, without neither the need of surfactant nor coating. Additionally, numerical computations of the Navier-Stokes equations based on the quasi-steadiness assumption allow to provide an explanation to the underlying mechanism behind the drop formation and the mechanism of the dripping to jetting transition. Excellent predictions were also obtained for the droplet radius, as well as for the dripping-jetting transition, when varying the geometrical and fluid parameters, showing the ability of this configuration to enventually enhance the dripping regime. The monodispersity ensured by the dripping regime, the robustness of the fabrication technique, the optimization capabilities from the numerical modelling and the universality of the configuration confer to the Raydrop technology a very high potential in the race towards high-throughput droplet generation processes.

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Extracellular Heme Proteins Influence Bovine Myosatellite Cell Proliferation and the Color of Cell-Based Meat

Foods ◽

10.3390/foods8100521 ◽

2019 ◽

Vol 8 (10) ◽

pp. 521 ◽

Cited By ~ 12

Author(s):

Robin Simsa ◽

John Yuen ◽

Andrew Stout ◽

Natalie Rubio ◽

Per Fogelstrand ◽

...

Keyword(s):

Cell Proliferation ◽

Heme Proteins ◽

Culture Media ◽

Growth Parameters ◽

Meat Production ◽

Human Consumption ◽

Efficient Production ◽

Produce Cell ◽

Negative Effect ◽

3D Printed

Skeletal muscle-tissue engineering can be applied to produce cell-based meat for human consumption, but growth parameters need to be optimized for efficient production and similarity to traditional meat. The addition of heme proteins to plant-based meat alternatives was recently shown to increase meat-like flavor and natural color. To evaluate whether heme proteins also have a positive effect on cell-based meat production, bovine muscle satellite cells (BSCs) were grown in the presence of hemoglobin (Hb) or myoglobin (Mb) for up to nine days in a fibrin hydrogel along 3D-printed anchor-point constructs to generate bioartificial muscles (BAMs). The influence of heme proteins on cell proliferation, tissue development, and tissue color was analyzed. We found that the proliferation and metabolic activity of BSCs was significantly increased when Mb was added, while Hb had no, or a slightly negative, effect. Hb and, in particular, Mb application led to a very similar color of BAMs compared to cooked beef, which was not noticeable in groups without added heme proteins. Taken together, these results indicate a potential benefit of adding Mb to cell culture media for increased proliferation and adding Mb or Hb for the coloration of cell-based meat.

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High Throughput Nanoliposome Formation Using 3D Printed Microfluidic Flow Focusing Chips

Advanced Materials Technologies ◽

10.1002/admt.201800511 ◽

2019 ◽

Vol 4 (6) ◽

pp. 1800511 ◽

Cited By ~ 8

Author(s):

Zhu Chen ◽

Jung Yeon Han ◽

Laura Shumate ◽

Renee Fedak ◽

Don L. DeVoe

Keyword(s):

High Throughput ◽

Flow Focusing ◽

Microfluidic Flow ◽

3D Printed

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High-Throughput Production of Micrometer Sized Double Emulsions and Microgel Capsules in Parallelized 3D Printed Microfluidic Devices

Polymers ◽

10.3390/polym11111887 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1887 ◽

Cited By ~ 2

Author(s):

Alexander Jans ◽

Jonas Lölsberg ◽

Abdolrahman Omidinia-Anarkoli ◽

Robin Viermann ◽

Martin Möller ◽

...

Keyword(s):

Surface Modification ◽

High Throughput ◽

Hollow Sphere ◽

Double Emulsion ◽

Continuous Phase ◽

Flow Focusing ◽

Double Emulsions ◽

Emulsion Droplets ◽

3D Printed ◽

Double Emulsion Droplets

Double emulsions are useful geometries as templates for core-shell particles, hollow sphere capsules, and for the production of biomedical delivery vehicles. In microfluidics, two approaches are currently being pursued for the preparation of microfluidic double emulsion devices. The first approach utilizes soft lithography, where many identical double-flow-focusing channel geometries are produced in a hydrophobic silicone matrix. This technique requires selective surface modification of the respective channel sections to facilitate alternating wetting conditions of the channel walls to obtain monodisperse double emulsion droplets. The second technique relies on tapered glass capillaries, which are coaxially aligned, so that double emulsions are produced after flow focusing of two co-flowing streams. This technique does not require surface modification of the capillaries, as only the continuous phase is in contact with the emulsifying orifice; however, these devices cannot be fabricated in a reproducible manner, which results in polydisperse double emulsion droplets, if these capillary devices were to be parallelized. Here, we present 3D printing as a means to generate four identical and parallelized capillary device architectures, which produce monodisperse double emulsions with droplet diameters in the range of 500 µm. We demonstrate high throughput synthesis of W/O/W and O/W/O double emulsions, without the need for time-consuming surface treatment of the 3D printed microfluidic device architecture. Finally, we show that we can apply this device platform to generate hollow sphere microgels.

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