Sensitive and predictable separation of microfluidic droplets by size using in-line passive filter

Ung, W. Lloyd; Heyman, John A.; Weitz, David A.

doi:10.1063/1.4976723

Cited by 14 publications

(9 citation statements)

References 21 publications

(29 reference statements)

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“…If homogeneous size is required, filtering of the GUVs in the droplet-stabilized state is an option. 44,45 Note that dsGUVs can in principle be reinjected into a microfluidic device for further manipulation, e.g., via pico-injection, for observation or sorting. 2 This work, greatly scaling up and simplifying synthetic cell assembly, will lead to GUV-based multicomponent synthetic cells of unprecedented complexity, shifting paradigms for bottom-up synthetic biology.…”

Section: Resultsmentioning

confidence: 99%

One-Pot Assembly of Complex Giant Unilamellar Vesicle-Based Synthetic Cells

et al. 2019

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Here, we introduce a one-pot method for the bottom-up assembly of complex single- and multicompartment synthetic cells. Cellular components are enclosed within giant unilamellar vesicles (GUVs), produced at the milliliter scale directly from small unilamellar vesicles (SUVs) or proteoliposomes with only basic laboratory equipment within minutes. Toward this end, we layer an aqueous solution, containing SUVs and all biocomponents, on top of an oil–surfactant mix. Manual shaking induces the spontaneous formation of surfactant-stabilized water-in-oil droplets with a spherical supported lipid bilayer at their periphery. Finally, to release GUV-based synthetic cells from the oil and the surfactant shell into the physiological environment, we add an aqueous buffer and a droplet-destabilizing agent. We prove that the obtained GUVs are unilamellar by reconstituting the pore-forming membrane protein α-hemolysin and assess the membrane quality with cryotransmission electron microscopy (cryoTEM), fluorescence recovery after photobleaching (FRAP), and zeta-potential measurements as well as confocal fluorescence imaging. We further demonstrate that our GUV formation method overcomes key challenges of standard techniques, offering high volumes, a flexible choice of lipid compositions and buffer conditions, straightforward coreconstitution of proteins, and a high encapsulation efficiency of biomolecules and even large cargo including cells. We thereby provide a simple, robust, and broadly applicable strategy to mass-produce complex multicomponent GUVs for high-throughput testing in synthetic biology and biomedicine, which can directly be implemented in laboratories around the world.

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Section: Resultsmentioning

confidence: 99%

One-Pot Assembly of Complex Giant Unilamellar Vesicle-Based Synthetic Cells

et al. 2019

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“…If such noncontact magnetic filtering could also work with a nongaseous surrounding fluid medium to obviate the need for direct physical contact with an actual filter material, 37 then many more filtering applications for such "true" emulsions might be possible.…”

Section: Resultsmentioning

confidence: 99%

Numerical study of ferro‐droplet breakup initiation induced by a slowly rotating uniform magnetic field

Radcliffe

2020

Engineering Reports

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The fully three-dimensional start-up deformations and accelerations of initially spherical magnetically susceptable linearly magnetizable ferrofluid droplets, driven by a rotating uniform magnetic field, are investigated through the use of coupled finite element/boundary element computer simulations. For given magnetic susceptability, a critical viscosity is suggested, proportional to both magnetic field strength and rotation speed, below which the deformations of the initially spherical droplet inevitably lead to breakup, but above which a simple persistent spheroidal solid body rotation is attained. K E Y W O R D Sdroplet deformations, ferrofluids, finite/boundary elements, rotating magnetic field INTRODUCTIONA ferrofluid is a non-electrically conducting, stable colloidal suspension of magnetic particles in a Newtonian carrier liquid that makes the latter sensitive to the presence of a magnetic field. 1 Such "ferrohydrodynamics" (FHD) are distinguishable from the "magnetohydrodynamics" (MHD) of electrically conducting fluids by the complete absence of electric currents and the Lorentz forces they might otherwise induce. The particles typically have sizes of about 10 nm and are often coated with a stabilizing dispersing agent (surfactant) to avoid particle agglomeration 2 -even in the presence of strong magnetic field gradients. Additionally, if the particles are also "magnetically soft," with a magnetization relaxation time of the order 10 −7 seconds, then hysteresis effects may also be neglected, as will be done here.Finally, a ferrofluid in droplet form gives a rich and varied phenomenology of physical behavior through the competition between magnetic and surface tension forces on the surface, in an analogous manner to that seen between electric and surface tension forces in electrohydrodynamics. [3][4][5] There have been many experimental 6-8 and numerical [8][9][10][11][12] studies of the simple axisymmetric prolate spheroid equilibrium shapes ferrodrops achieve inside static uniform applied magnetic fields analogous to those of dielectric drops in an electric field, [13][14][15][16] where the prolate elongation from a sphere aligns with the applied field direction and assumes a stable equilibrium configuration directly proportional to the field strength.However, if the external magnetic field rotates, then two distinct classes of behavior emerge, dependent on the rotation speed.

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“…For an overview of the pros and cons of droplet microfluidics for single cell separation, analysis and diagnostics, please refer to Table 8 below. Individual droplets can be handled, for example, using acoustophoresis/SAW [134,167], hydrodynamic or microfluidic changes by geometries [168][169][170][171], elective emulsion separation [172], in-line passive filters [173], or even DLD [99]. It is also possible to manipulate the contents inside these droplets using DEP [174,175], magnetic fields [176,177], or beads and microfluidic ratchets [178].…”

Section: Droplet Microfluidicsmentioning

confidence: 99%

Lab-on-a-Chip Technologies for the Single Cell Level: Separation, Analysis, and Diagnostics

Hochstetter

2020

Micromachines

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In the last three decades, microfluidics and its applications have been on an exponential rise, including approaches to isolate rare cells and diagnose diseases on the single-cell level. The techniques mentioned herein have already had significant impacts in our lives, from in-the-field diagnosis of disease and parasitic infections, through home fertility tests, to uncovering the interactions between SARS-CoV-2 and their host cells. This review gives an overview of the field in general and the most notable developments of the last five years, in three parts: 1. What can we detect? 2. Which detection technologies are used in which setting? 3. How do these techniques work? Finally, this review discusses potentials, shortfalls, and an outlook on future developments, especially in respect to the funding landscape and the field-application of these chips.

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Sensitive and predictable separation of microfluidic droplets by size using in-line passive filter

Cited by 14 publications

References 21 publications

One-Pot Assembly of Complex Giant Unilamellar Vesicle-Based Synthetic Cells

One-Pot Assembly of Complex Giant Unilamellar Vesicle-Based Synthetic Cells

Numerical study of ferro‐droplet breakup initiation induced by a slowly rotating uniform magnetic field

Lab-on-a-Chip Technologies for the Single Cell Level: Separation, Analysis, and Diagnostics

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