Numerical study of thermocoalescence of microdroplets in a microfluidic chamber

Ho, Peng Ching; Nguyen, Nam‐Trung

doi:10.1063/1.4819134

Cited by 5 publications

(3 citation statements)

References 25 publications

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“…S7) when the surface tension and viscosity are functions of temperature agreed with the results presented by Ho et al . 36 .…”

Section: Resultsmentioning

confidence: 99%

“…To the authors’ knowledge, the only 3D numerical model of droplet formation in a heated T-junction microchannel was presented by Ho et al . 36 , where they considered the effect of temperature-dependant properties and thermos-coalescence on droplet transport. It is noticeable that the physics governing the thermo-microfluidics require further understanding due to the strong coupling of different physical phenomena.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of temperature-actuated droplets within microfluidics

Khater

Mohammadi

Mohamad

et al. 2019

Sci Rep

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Characterizing the thermal behavior of dispersed droplets within microfluidic channels is crucial for different applications in lab-on-a-chip. In this paper, the physics of droplets volume during their transport over a heater is studied experimentally and numerically. The response of droplets to external heating is examined at temperature ranges of 25–90 °C and at different flow rates of the dispersed phase respect to the continuous flow. The results present a reliable prediction of the droplet volume and stability when heating is applied to the droplets at the downstream channel in a quite far distance from the droplets’ ejection orifice. Increasing the ratio of flow rate resulted in larger droplets; for instance, the flow ratio of 0.25 produced drops with 40% larger diameter than the flow rate of 0.1. For every 10 °C increase in temperature of the droplets, the droplet diameter increased by about 5.7% and 4.2% for pure oil and oil with a surfactant, respectively. Also, the droplets showed a degree of instability during their transport over the heater at higher temperatures. Adding SPAN 20 surfactant improved the stability of the droplets at temperatures higher than 60 °C. The experimentally validated numerical model helped for systemic analysis of the influence of key temperature-dependence parameters (e.g. surface tension, density and viscosity of both phases) on controlling the volume and stability of droplets. Our findings supported to develop highly functional systems with a predetermined droplets performance under high temperatures up to 90 °C. This report provides a preliminary basis for enhancing the performance of droplet microfluidic systems for digital droplet polymerase chain reaction (ddPCR), continuous flow digital loop-mediated isothermal PCR (LAMP), and droplet-based antibiotic susceptibility testing.

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“…S7) when the surface tension and viscosity are functions of temperature agreed with the results presented by Ho et al . 36 .…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of temperature-actuated droplets within microfluidics

Khater

Mohammadi

Mohamad

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…However, the temperature dependency of droplet physical properties represented by density, viscosity, and interfacial tension between the continuous oil phase and water-based droplet may complicate high-performance droplet microfluidics. Further, the mathematical simulation of droplet behavior under heating is complicated due to the necessity of 3D models of a droplet-based system 11 . In addition to the investigation of the temperature dependence of a droplet's physical properties with localized heating on the microfluidic chip, the creation of on-chip ∇T has been challenging as one can study microtubule polymerization 12 along the ∇T or MCA for single nucleotide polymorphisms 13 , both performed in a flow-through configuration.…”

mentioning

confidence: 99%

Rapid Characterization of Biomolecules’ Thermal Stability in a Segmented Flow-Through Optofluidic Microsystem

Fohlerová

Zhu

Hubálek

et al. 2020

Sci Rep

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Optofluidic devices combining optics and microfluidics have recently attracted attention for biomolecular analysis due to their high detection sensitivity. Here, we show a silicon chip with tubular microchannels buried inside the substrate featuring temperature gradient (∇T) along the microchannel. We set up an optical fluorescence system consisting of a power-modulated laser light source of 470 nm coupled to the microchannel serving as a light guide via optical fiber. Fluorescence was detected on the other side of the microchannel using a photomultiplier tube connected to an optical fiber via a fluorescein isothiocyanate filter. The PMT output was connected to a lock-in amplifier for signal processing. We performed a melting curve analysis of a short dsDNA-SYBR Green I complex with a known melting temperature (T M) in a flow-through configuration without gradient to verify the functionality of the proposed detection system. We then used the segmented flow configuration and measured the fluorescence amplitude of a droplet exposed to ∇T of ≈ 2.31 °C mm −1 , determining the heat transfer time as ≈ 554 ms. The proposed platform can be used as a fast and cost-effective system for performing either MCA of dsDNAs or for measuring protein unfolding for drug-screening applications.

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