Hands-Off Preparation of Monodisperse Emulsion Droplets Using a Poly(dimethylsiloxane) Microfluidic Chip for Droplet Digital PCR

Tanaka, Hironari; Yamamoto, Shunsuke; Nakamura, Arichika; Nakashoji, Yuta; Okura, Naoaki; Nakamoto, Norimitsu; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

doi:10.1021/ac503169h

Cited by 64 publications

(51 citation statements)

References 30 publications

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“…3b, produce droplets with radius CV of 0.5%. These droplets are more monodisperse than those produced through other recently developed methods, which all report polydispersity > 1% [7,12,13,14,16,17,18,19,20]. It should be noted that our measurement of droplet radius CV is limited by the precision with which we are able to measure individual droplet radii (∼ 60 nm), and so the quoted value represents an upper bound on the actual radius CV.…”

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confidence: 82%

Snap-off production of monodisperse droplets

2015

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Abstract. We introduce a novel technique to produce monodisperse droplets through the snap-off mechanism. The methodology is simple, versatile, and requires no specialized or expensive components. The droplets produced have polydispersity < 1% and can be as small as 2.5 µm radius. A convenient feature is that the droplet size is constant over a 100-fold change in flow rate, while at higher flows the droplet size can be continuously adjusted.Microfluidics applications often require emulsions with a wide range of characteristics, prompting the development of several distinct techniques for producing droplets [1,2]. One important parameter is the degree of polydispersity among droplet sizes, where smaller values are preferable for many applications. Droplets with an extremely low polydispersity are particularly desirable for basic science investigations of emulsions [3,4], vessels for tiny experiments [5,6,7], as well as calibration in both academic and industrial settings [8]. Here we present a method we have recently developed using glass capillaries and a surface tension driven 'snap-off' instability to produce droplets. This method is remarkable for its simplicity, ease of implementation, and the high monodispersity of droplets produced. An additional convenience is that there are two distinct regimes of droplet production: 1) the size of droplets is insensitive at low flow rates; while, 2) at high flow rates the droplet size is tunable.The snap-off instability of droplets in cylindrically symmetric capillaries was first described in 1970 [9], and has since been investigated further in the context of understanding the physics behind snap-off [10,11]. We took advantage of this effect to develop a versatile system for production of monodisperse droplets that is easy to assemble and operate. One important consideration is that this setup requires no flow of the continuous phase, since the pinch-off is driven by surface tension forces rather than viscous forces. Although the snap-off process has been used previously to produce droplets in flattened microfluidic geometries [12,13,14], our simple cylindrical configuration is able to produce droplets that are more monodisperse.In order to prepare monodisperse droplets we have utilised a method that is schematically depicted in Fig.

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confidence: 82%

Snap-off production of monodisperse droplets

2015

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“…Several preparation techniques have been reported, which include the preparation of monodispersed emulsions. 1,2 Furthermore, multiple emulsions exist, such as a water-in-oil-inwater (W/O/W) emulsion and an oil-in-water-in-oil (O/W/O) emulsion, and new preparation techniques for controllable monodispersed multiple emulsions have recently been reported. 3,4 Emulsions are widely applied in academic fields: liquid-liquid extraction or dispersive liquid-liquid microextraction is often used in analytical chemistry [5][6][7][8][9][10] and emulsion polymerization is common in polymer chemistry.…”

Section: Introductionmentioning

confidence: 99%

Time-Profile Measurement of an Emulsion Using Multiphoton Ionization Time-of-Flight Mass Spectrometry in Combination with a Microscope

Shimo

Uchimura

2016

ANAL. SCI.

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Multiphoton ionization time-of-flight mass spectrometry was applied to the measurement of an oil-in-water emulsion that contained toluene as a dispersed phase. Before the measurement, the sample was sufficiently creamed, and then stirred for a short period of time for dispersion. As a result, several intense spikes appeared on the time profile constructed from the peak area for toluene. In the present study, an optical microscope was used to observe the capillary column for sample introduction, and small toluene droplets along with their aggregates were found in the images of the emulsion flowing through the capillary. The aggregates produced intense spikes comprised of multiple plots, which could be easily marked by applying a moving median filter. In the present study, droplets with minimum diameters as small as 2.9 μm, which corresponds to 13 fL, could be calculated as detectable spikes.

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“…Emulsions are used in diverse applications such as foods, cosmetics, and pharmaceuticals. Many studies have been carried out concerning emulsions; in recent years, novel techniques for the preparation [1][2][3][4] and measurement/evaluation [5][6][7][8][9][10][11][12] of emulsions or droplets have been reported. Chen et al reported in situ monitoring of emulsion polymerization by Raman spectroscopy using a homopolymer as an internal standard, although the absolute Raman intensity depends on many factors, such as the solution turbidity and the particle size distribution of the dispersed phase.…”

Section: Introductionmentioning

confidence: 99%