Precise pooling and dispensing of microfluidic droplets towards micro- to macro-world interfacing

Brouzés, Eric; Carniol, April; Bakowski, Tomasz; Strey, Helmut H.

doi:10.1039/c4ra07110g

Cited by 7 publications

(5 citation statements)

References 30 publications

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“…In all cases, the decrease in interfacial energy is at least 20 mN/m compared to the pure oil, which qualifies those surfactants as good surfactant for droplet microfluidics following previously established criteria. 17 The value of the interfacial energy of the PFPE-PEG surfactant 9 is slightly higher than we previously reported 64 but in the range reported by others; 8 however, the value of its critical micellar concentration is one order of magnitude higher than previously reported by the same group. During synthesis, we have degraded any impurities into non surface-active impurities through decarboxylation.…”

Section: Resultscontrasting

confidence: 41%

Click chemistry approaches to expand the repertoire of PEG-based fluorinated surfactants for droplet microfluidics

et al. 2018

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We report the novel and simplified synthesis of fluorinated surfactants for droplet microfluidics. The range of applications of droplet microfluidics has greatly expanded during the last decade thanks to its ability to manipulate and process tiny amount of sample and reagents at high throughput in independent reactors. A critical component of the technology is the formulation of the immiscible oil phase that contains surfactants to stabilize droplets. The success of droplet microfluidics relies mostly on a single fluorinated formulation that uses a PFPE-PEG tri-block surfactant. The synthesis of this surfactant is laborious and requires skills in synthetic chemistry preventing the wider community to explore the synthesis of alternate surfactants. We sought to provide a simplified synthesis for novel PFPE-PEG surfactants based on click chemistry approaches such as copper-catalyzed azide-alkyne cycloaddition (CuAAC) and UV-activated thiol-yne reactions. Our strategy is based on converting a moisture sensitive intermediate typically used in the synthesis of the tri-block PFPE-PEG surfactant into a stable and click ready molecule. We successfully combined that fluorinated tail with differently functionalized PEG and glycerol ethoxylate molecules to generate surfactants with diverse structures via CuACC and thiol-yne reactions. We report the characterization, biocompatibility and ability to stabilize emulsions of those surfactants, as well as the unique advantages and challenges of the strategy.

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Section: Resultscontrasting

confidence: 41%

Click chemistry approaches to expand the repertoire of PEG-based fluorinated surfactants for droplet microfluidics

et al. 2018

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“…Alternatively, we could also expand the velocity range where capillarity affects the splitting profile by using a droplet system with higher interfacial tension. For instance, the interfacial tension of a water and fluorinated oil containing 1% weight PEG-based surfactant has a value of 1 mN/m for the HFE7500 oil but a value of 20 mN/m for the FC-40 oil 66, 67 .…”

Section: Resultsmentioning

confidence: 99%

“…For instance, the interfacial tension of a water and fluorinated oil containing 1% weight PEG-based surfactant has a value of 1 mN m −1 for the HFE7500 oil but a value of 20 mN m −1 for the FC-40 oil. 66,67 The throughput of the magnetic bead separation at 98.1% retention of magnetic beads is about 15 droplets per second at 6 mm s −1 in the case where droplets are separated by two droplet lengths. The upper limit of throughput for droplet microfluidics is usually set by droplet generation, while we expect to perform droplet manipulations at one order of magnitude lower throughput.…”

Section: Characterizing the Optimized Design For Magnetic Bead Extrac...mentioning

confidence: 99%

Rapid and continuous magnetic separation in droplet microfluidic devices

et al. 2015

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We present a droplet microfluidic method to extract molecules of interest from a droplet in a rapid and continuous fashion. We accomplish this by first marginalizing functionalized super-paramagnetic beads within the droplet using a magnetic field, and then splitting the droplet into one droplet containing the majority of magnetic beads and one droplet containing the minority fraction. We quantitatively analysed the factors which affect the efficiency of marginalization and droplet splitting to optimize the enrichment of magnetic beads. We first characterized the interplay between the droplet velocity and the strength of the magnetic field and its effect on marginalization. We found that marginalization is optimal at the midline of the magnet and that marginalization is a good predictor of bead enrichment through splitting at low to moderate droplet velocities. Finally, we focused our efforts on manipulating the splitting profile to improve the enrichment provided by asymmetric splitting. We designed asymmetric splitting forks that employ capillary effects to preferentially extract the bead-rich regions of the droplets. Our strategy represents a framework to optimize magnetic bead enrichment methods tailored to the requirements of specific droplet-based applications. We anticipate that our separation technology is well suited for applications in single-cell genomics and proteomics. In particular, our method could be used to separate mRNA bound to poly-dT functionalized magnetic microparticles from single cell lysates to prepare single-cell cDNA libraries.

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“…The basic principle of forming SDA follows hydrodynamic trapping previously reported by pioneering groups. 25,30,[41][42][43] As shown in Fig. 1B, a SDA consists of a series of bypass loop channels superimposed onto a straight hydrodynamic trap.…”

Section: Resultsmentioning

confidence: 99%

Microfluidic static droplet array for analyzing microbial communication on a population gradient

et al. 2015

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Quorum sensing (QS) is a type of cell-cell communication using signal molecules that are released and detected by cells, which respond to changes in their population density. A few studies explain that QS may operate in a density-dependent manner; however, due to experimental challenges, this fundamental hypothesis has never been investigated. Here, we present a microfluidic static droplet array (SDA) that combines a droplet generator with hydrodynamic traps to independently generate a bacterial population gradient into a parallel series of droplets under complete chemical and physical isolation. The SDA independently manipulates both a chemical concentration gradient and a bacterial population density. In addition, the bacterial population gradient in the SDA can be tuned by a simple change in the number of sample plug loading. Finally, the method allows the direct analysis of complicated biological events in an addressable droplet to enable the characterization of bacterial communication in response to the ratio of two microbial populations, including two genetically engineered QS circuits, such as the signal sender for acyl-homoserine lactone (AHL) production and the signal receiver bacteria for green fluorescent protein (GFP) expression induced by AHL. For the first time, we found that the population ratio of the signal sender and receiver indicates a significant and potentially interesting partnership between microbial communities. Therefore, we envision that this simple SDA could be a useful platform in various research fields, including analytical chemistry, combinatorial chemistry, synthetic biology, microbiology, and molecular biology.

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Precise pooling and dispensing of microfluidic droplets towards micro- to macro-world interfacing

Cited by 7 publications

References 30 publications

Click chemistry approaches to expand the repertoire of PEG-based fluorinated surfactants for droplet microfluidics

Click chemistry approaches to expand the repertoire of PEG-based fluorinated surfactants for droplet microfluidics

Rapid and continuous magnetic separation in droplet microfluidic devices

Microfluidic static droplet array for analyzing microbial communication on a population gradient

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