Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails

Yoon, Dong Hyun; Tanaka, Daiki; Sekiguchi, Tetsushi; Shoji, Shuichi

doi:10.3390/mi9100513

Cited by 8 publications

(5 citation statements)

References 42 publications

(43 reference statements)

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“…This sorting is accomplished by employing both passive and active methods. Size-dependent sorting relies upon channel geometry that deflects the flow of smaller particles away from the main flow channel [ 181 , 182 ]. Gravity-based sorting, on the other hand, relies on the difference between the sedimentation velocity of larger particles and smaller particles at a given density [ 183 ].…”

Section: Droplet-based Microfluidics: Speciation In Actionmentioning

confidence: 99%

Origin of Species before Origin of Life: The Role of Speciation in Chemical Evolution

Jia

Caudan

Mamajanov

2021

Life

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Speciation, an evolutionary process by which new species form, is ultimately responsible for the incredible biodiversity that we observe on Earth every day. Such biodiversity is one of the critical features which contributes to the survivability of biospheres and modern life. While speciation and biodiversity have been amply studied in organismic evolution and modern life, it has not yet been applied to a great extent to understanding the evolutionary dynamics of primitive life. In particular, one unanswered question is at what point in the history of life did speciation as a phenomenon emerge in the first place. Here, we discuss the mechanisms by which speciation could have occurred before the origins of life in the context of chemical evolution. Specifically, we discuss that primitive compartments formed before the emergence of the last universal common ancestor (LUCA) could have provided a mechanism by which primitive chemical systems underwent speciation. In particular, we introduce a variety of primitive compartment structures, and associated functions, that may have plausibly been present on early Earth, followed by examples of both discriminate and indiscriminate speciation affected by primitive modes of compartmentalization. Finally, we discuss modern technologies, in particular, droplet microfluidics, that can be applied to studying speciation phenomena in the laboratory over short timescales. We hope that this discussion highlights the current areas of need in further studies on primitive speciation phenomena while simultaneously proposing directions as important areas of study to the origins of life.

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Section: Droplet-based Microfluidics: Speciation In Actionmentioning

confidence: 99%

Origin of Species before Origin of Life: The Role of Speciation in Chemical Evolution

Jia

Caudan

Mamajanov

2021

Life

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“…The trapping of the big droplets was optimized first and required fine tuning, as this step is performed first ( Figure 4 A,B) and the small droplet trapping is performed only when all big droplet traps are filled ( Figure 4 C). This step requires d trap (big) to be wide enough to attract big droplets from the rail towards the trap ( Figure 4 B) but also narrow enough to prevent double droplet trapping (big droplets go both in the small and big traps) [ 7 , 9 ]. It appears that the big droplet trapping efficiency in big traps is not influenced by the absence or presence of rails and remains at 100% in all conditions ( Figure 4 E).…”

Section: Resultsmentioning

confidence: 99%

“…However, the most widely spread droplet size-based sorting combines two passive mechanisms: Laplace’s trapping mechanism and the hydrodynamic drag force. This method implies the use of structured features located at the top or bottom of the microchannels to guide the confined droplets through the use of continuous [ 7 ] or “dotted” guiding tracks [ 8 , 9 ]. Yoon et al [ 7 ] developed the “railing” method for size-based filtration with the aim of simplifying droplet sorting, which was previously performed using optical control of droplet content and active control sample systems (based on electric, ultrasonic, hydrodynamic or optical forces).…”

Section: Introductionmentioning

confidence: 99%

“…Yoon et al [ 7 ] developed the “railing” method for size-based filtration with the aim of simplifying droplet sorting, which was previously performed using optical control of droplet content and active control sample systems (based on electric, ultrasonic, hydrodynamic or optical forces). In a later study, Yoon’s team also suggested the used of dotted lines instead of rails [ 9 ]. The railing system was recently further developed and complexified by Rehman [ 8 ], using multiple rails to discriminate more than two droplet sizes.…”

Section: Introductionmentioning

confidence: 99%

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Microfluidic Device for Droplet Pairing by Combining Droplet Railing and Floating Trap Arrays

et al. 2021

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Droplet microfluidics are characterized by the generation and manipulation of discrete volumes of solutions, generated with the use of immiscible phases. Those droplets can then be controlled, transported, analyzed or their content modified. In this wide droplet microfluidic toolbox, no means are available to generate, in a controlled manner, droplets co-encapsulating to aqueous phases. Indeed, current methods rely on random co-encapsulation of two aqueous phases during droplet generation or the merging of two random droplets containing different aqueous phases. In this study, we present a novel droplet microfluidic device to reliably and efficiently co-encapsulate two different aqueous phases in micro-droplets. In order to achieve this, we combined existing droplet microfluidic modules in a novel way. The different aqueous phases are individually encapsulated in droplets of different sizes. Those droplet populations are then filtered in order to position each droplet type towards its adequate trapping compartment in traps of a floating trap array. Single droplets, each containing a different aqueous phase, are thus paired and then merged. This pairing at high efficiency is achieved thanks to a unique combination of floating trap arrays, a droplet railing system and a droplet size-based filtering mechanism. The microfluidic chip design presented here provides a filtering threshold with droplets larger than 35 μm (big droplets) being deviated to the lower rail while droplets smaller than 20 μm (small droplets) remain on the upper rail. The effects of the rail height and the distance between the two (upper and lower) rails were investigated. The optimal trap dimensions provide a trapping efficiency of 100% for small and big droplets with a limited double trapping (both compartments of the traps filled with the same droplet type) of 5%. The use of electrocoalescence enables the generation of a droplet while co-encapsulating two aqueous phases. Using the presented microfluidic device libraries of 300 droplets, dual aqueous content can be generated in less than 30 min.

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“…There are passive and active methods to produce and control microdroplets [10]. The active method employs external forces to interrupt the continuous flow between the fluids, while the passive method takes advantages from the geometry designs, the fluids injection and the fluid flow regimes to produce droplets inside the microchannels [8,11]. In terms of microfluidic architectures to generate microdroplets, the cross-flow geometries are widely used due the simplicity in the manufacture of the devices and the ability to reproduce monodisperse droplets [8].…”

Section: Introductionmentioning

confidence: 99%

Microfluidic system manufacturing by direct laser writing for the generation and characterization of microdroplets

Álvarez-Martínez¹,

Medina-Cázares²,

Alcaraz³

et al. 2022

J. Micromech. Microeng.

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This work contributes to the development of microfluidics devices in a simpler way and by keeping the cost of microfabrication as low as possible. Implementing methods to develop microfluidic devices and to have control over the channel size rapidly and easily have become a challenge. In the present work, direct laser writing (DLW) is proposed as a manufacturing technique to develop a T-junction microfluidic droplet generator operating in the squeezing regime. Owing to the channel size, DLW depends on both the focused laser spot properties and the interface material refractive indices. The Debye-Wolf theory behind this technique predicts the focal shift of the laser spot to avoid optical misalignment during the fabrication process. The Debye-Wolf theory and the COMSOL ray-tracing module are presented as complementary design tools. The flow rates and the channel sizes were investigated under the two-phase COMSOL module. Experimental droplet generation results were assisted with the solution of the Navier-Stokes equation with appropriate boundary conditions. Microdroplet size characterization, as well as simulations, show a linear tendency with the flow rate ratios (FRR). For FRR ranging from 0.25 to 2, droplet lengths from ∼ 320μm to ∼ 1050μm were observed. This information is confirmed by implementing a digital image processing protocol. The dynamics of droplets formation, strongly influenced by the input flow rate fluctuations caused by the syringes and micropump operation, are presented. This protocol aims the full control of these devices to perform potential applications, such as particle insulators, drug delivery, fluidic microlasers, among others.

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Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails

Cited by 8 publications

References 42 publications

Origin of Species before Origin of Life: The Role of Speciation in Chemical Evolution

Origin of Species before Origin of Life: The Role of Speciation in Chemical Evolution

Microfluidic Device for Droplet Pairing by Combining Droplet Railing and Floating Trap Arrays

Microfluidic system manufacturing by direct laser writing for the generation and characterization of microdroplets

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