Microneedle-assisted microfluidic flow focusing for versatile and high throughput water-in-water droplet generation

Jeyhani, Morteza; Gnyawali, Vaskar; Abbasi, Niki; Hwang, Dae Kun; Tsai, Scott S. H.

doi:10.1016/j.jcis.2019.05.100

Cited by 34 publications

(41 citation statements)

References 59 publications

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“…To fabricate the hybrid device, the chip was modified to coaxially focus the flows in a 3D configuration and isolate dispersed phases from the channel walls . To do so, a cylindrical glass capillary (ID = 150 µm, OD = 250 µm; Whale Apparatus, Hellertown, PA) was first cut to a length of 7 mm, using a ceramic tile (Shutter Instrument Co., Novato, CA).…”

Section: Methodsmentioning

confidence: 99%

“…Traditionally, these systems are used for different biotechnological applications, such as partitioning of biomolecules, and cell patterning . In recent years, techniques for microfluidically generating of water‐in‐water (W/W) droplets are emerging using both active and passive approaches. Despite these advances in generating single W/W droplets, there is very little work done in making higher‐order all‐aqueous biocompatible emulsions, where one or more intermediate phases separate the innermost core from the continuous phase.…”

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

“…We show, for the first time, a PDMS‐based microfluidic device, which we call a hybrid device, that can generate multiple emulsions by injecting phase‐separated aqueous phases using pressure pumps. We use a microneedle‐assisted flow‐focusing design with a coaxially embedded glass capillary that is positioned downstream of the flow inlets, inside the channel, at the second flow‐focusing junction. This approach facilitates the isolation of the dispersed phases from the channel walls, which prevents wetting issues from occurring within the PDMS‐based microfluidic channel, without any chemical surface treatment procedures .…”

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

“…In this work, we describe a microfluidic platform for the generation of all‐aqueous double and triple emulsions based on ATPS. Our platform consists of a conventional multi cross‐junction flow‐focusing device, with a microneedle inserted into the first inlet followed by the embedding of one or two glass capillaries inside the microchannel between different cross‐junctions. The glass capillaries help to prevent wetting of the microchannel walls by the disperse phases.…”

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

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Microfluidic Generation of All‐Aqueous Double and Triple Emulsions

Jeyhani

Thevakumaran

Abbasi

et al. 2020

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Higher order emulsions are used in a variety of different applications in biomedicine, biological studies, cosmetics, and the food industry. Conventional droplet generation platforms for making higher order emulsions use organic solvents as the continuous phase, which is not biocompatible and as a result, further washing steps are required to remove the toxic continuous phase. Recently, droplet generation based on aqueous two‐phase systems (ATPS) has emerged in the field of droplet microfluidics due to their intrinsic biocompatibility. Here, a platform to generate all‐aqueous double and triple emulsions by introducing pressure‐driven flows inside a microfluidic hybrid device is presented. This system uses a conventional microfluidic flow‐focusing geometry coupled with a coaxial microneedle and a glass capillary embedded in flow‐focusing junctions. The configuration of the hybrid device enables the focusing of two coaxial two‐phase streams, which helps to avoid commonly observed channel‐wetting problems. It is shown that this approach achieves the fabrication of higher‐order emulsions in a poly(dimethylsiloxane)‐based microfluidic device, and controls the structure of the all‐aqueous emulsions. This hybrid microfluidic approach allows for facile higher‐order biocompatible emulsion formation, and it is anticipated that this platform will find utility for generating biocompatible materials for various biotechnological applications.

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Section: Methodsmentioning

confidence: 99%

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

Section: Concentration Of Stock Solutions and Equilibrated Peg‐rich Amentioning

confidence: 99%

See 2 more Smart Citations

Microfluidic Generation of All‐Aqueous Double and Triple Emulsions

Jeyhani

Thevakumaran

Abbasi

et al. 2020

Small

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“…Complex statistics needed to sort analysis data Difficult to perform long-term culture Droplet generation [188,189]; Mixing inside droplet [160,190]; Droplet-based microfluidic PCR [179];…”

Section: High-throughput Screening Systems: Microfluidic Devicesmentioning

confidence: 99%

Challenges in Bone Tissue Regeneration: Stem Cell Therapy, Biofunctionality and Antimicrobial Properties of Novel Materials and Its Evolution

Riester

Borgolte

Csuk

et al. 2020

IJMS

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An aging population leads to increasing demand for sustained quality of life with the aid of novel implants. Patients expect fast healing and few complications after surgery. Increased biofunctionality and antimicrobial behavior of implants, in combination with supportive stem cell therapy, can meet these expectations. Recent research in the field of bone implants and the implementation of autologous mesenchymal stem cells in the treatment of bone defects is outlined and evaluated in this review. The article highlights several advantages, limitations and advances for metal-, ceramic- and polymer-based implants and discusses the future need for high-throughput screening systems used in the evaluation of novel developed materials and stem cell therapies. Automated cell culture systems, microarray assays or microfluidic devices are required to efficiently analyze the increasing number of new materials and stem cell-assisted therapies. Approaches described in the literature to improve biocompatibility, biofunctionality and stem cell differentiation efficiencies of implants range from the design of drug-laden nanoparticles to chemical modification and the selection of materials that mimic the natural tissue. Combining suitable implants with mesenchymal stem cell treatment promises to shorten healing time and increase treatment success. Most research studies focus on creating antibacterial materials or modifying implants with antibacterial coatings in order to address the increasing number of complications after surgeries that are mostly caused by bacterial infections. Moreover, treatment of multiresistant pathogens will pose even bigger challenges in hospitals in the future, according to the World Health Organization (WHO). These antibacterial materials will help to reduce infections after surgery and the number of antibiotic treatments that contribute to the emergence of new multiresistant pathogens, whilst the antibacterial implants will help reduce the amount of antibiotics used in clinical treatment.

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Scalable, Membrane‐Based Microfluidic Passive Cross‐Flow Platform for Monodispersed, Water‐in‐Water Microdroplet Production

Thompson

Hwang

2021

Adv Materials Inter

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diagnostics, [6] biomolecule evolution, [7] and food-grade quality control. [8] These applications use monodispersed picoliteror nanoliter-volume droplets, resulting in cost-effective and time-efficient procedures. [9] Classical microdroplet formation methods to form such microdroplets use oil and water as immiscible liquids. Oil, however, is a non-biocompatible medium that must be removed subsequent to droplet formation because the oil phase negatively impacts on encapsulated biological species, such as cells, in the water droplet phase. Thus, an additional step, typically a time-and labor-intensive oilremoval treatment, would be required. [10] Alternatively, aqueous two-phase systems (ATPSs) have recently made a high-impact appearance in the droplet formation field because of its biocompatibility. The applicability of ATPS as a medium for cells and biomolecules has been widely proven, allowing for it to be a reasonable option for biological applications and, furthermore, the elimination of post-processing washing. [11] ATPSs have been applied to partitioning and purification of proteins, [12] enzymes, [13,14] drug residues in food and water, [15,16] etc., as well as cell patterning [17] and fractionation. [18] There are many unique ATPS compositions available for implementation including, but not limited to, polymer-salt [19,20] and alcohol-salt. [21,22] The mixture of polyethylene glycol (PEG) and dextran (DEX) is a well-documented polymerpolymer composition that has been often-used for droplet formation. [23] The main challenge in the ATPS droplet formation is overcoming the ultra-low interfacial tension (< 1 mJ m −2 ) [24] of the two aqueous-phases making hydrodynamic thread break-up difficult and restricted to jetting droplet regimes. [25] For successful droplet break-up, active methods use external forces to overcome the viscous forces that stretch the interface between the aqueous continuous and dispersed phases. Active approaches thus require external components for flow perturbation, such as, piezo-electric disc actuation, [26,27] mechanical vibration, [28,29] inlet pressure pulsation, [30] and pneumatic valve control. [31] Recent passive approaches in flow focusing microfluidic platforms simplify the droplet formation mechanism by eliminating external component requirements. Passive methods canThe generation of water-in-water droplets has recently received great attention for its applicability in biological applications over traditional oil-water droplet systems because of their high biocompatibility. An aqueous twophase system (ATPS), aqueous mixture of polyethylene glycol (PEG) and dextran (DEX), has an ultra-low interfacial tension which makes monodispersed droplet formation challenging. Recent passive methods in microfluidics with flow-focusing configurations overcome this challenge, but they suffer either from polydispersity, narrow droplet size range, or low throughput. Successful droplet formation in such passive methods occurs in jetting flow regimes with low continuous phase flowrates, Q c < ...

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Microneedle-assisted microfluidic flow focusing for versatile and high throughput water-in-water droplet generation

Cited by 34 publications

References 59 publications

Microfluidic Generation of All‐Aqueous Double and Triple Emulsions

Microfluidic Generation of All‐Aqueous Double and Triple Emulsions

Challenges in Bone Tissue Regeneration: Stem Cell Therapy, Biofunctionality and Antimicrobial Properties of Novel Materials and Its Evolution

Scalable, Membrane‐Based Microfluidic Passive Cross‐Flow Platform for Monodispersed, Water‐in‐Water Microdroplet Production

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