PDMS droplet formation and characterization by hydrodynamic flow focusing technique in a PDMS square microchannel

Carneiro, João; Doutel, E.; Campos, J.B.L.M.; Miranda, J. M.

doi:10.1088/0960-1317/26/10/105013

Cited by 22 publications

(20 citation statements)

References 32 publications

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“…The boundary between the dripping and the jetting regimes obtained for a viscosity ratio of 0.33 is similar to the one obtained in previous work [4] for a viscosity ratio of 533, suggesting that the regime map is independent of the viscosity ratio. However it will be necessary to obtain more data points to define the boundary more accurately.…”

Section: Resultssupporting

confidence: 86%

“…The experiments were conducted in PDMS microchannels obtained by soft lithography from SU-8 molds, following our previous work [4]. No plasma treatment was applied to the microchannel, and so the surface was kept hydrophobic.…”

Section: Device Fabricationmentioning

confidence: 99%

“…The emulsion obtained was cooled at 5º C to solidify the droplets and form particles. Images of droplet formation were obtained through an inverted microscope by a high speed camera, following a previous procedure [4].…”

Section: Droplet Formationmentioning

confidence: 99%

See 2 more Smart Citations

Production of gelatin microparticles in a flow focusing microfluidic device for biomedical applications

Moreira¹,

Carneiro²,

Campos³

et al. 2019

Proceedings of the 4th World Congress on Momentum, Heat and Mass Transfer

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Particles that can mimetize some of the mechanical and geometrical properties of red blood cells and other cellular components of the human body can have important applications in the development of drug delivery carriers and blood substitutes. In this work gelatin microparticles are produced in a droplet microfluidics flow focusing device. Several operating conditions are studied and, for the best conditions, particles of 14-16 m are obtained. Two flow regimes are observed, dripping, when the Capillary number of the dispersed phase is smaller than 0.01, and jetting when the capillary number of the dispersed phase is higher than 0.01.

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Section: Resultssupporting

confidence: 86%

Section: Device Fabricationmentioning

confidence: 99%

See 1 more Smart Citation

Production of gelatin microparticles in a flow focusing microfluidic device for biomedical applications

Moreira¹,

Carneiro²,

Campos³

et al. 2019

Proceedings of the 4th World Congress on Momentum, Heat and Mass Transfer

View full text Add to dashboard Cite

show abstract

“…Droplet generation may be driven using active methods such as piezoelectric actuators and electric fields [15][16][17] , but monodisperse droplets are most commonly formed in continuous pressuredriven nozzles with flow-focusing or co-flowing method [7,16,[18][19][20] , or T-junction techniques [21][22][23] . Jian et al [24] and Muñoz-Sánchez et al [7] proposed a flow-focusing technique where a PDMS precursor was dispersed into microdroplets within a continuous phase.…”

Section: Introductionmentioning

confidence: 99%

“…Stiffness and deformability are particle characteristics that have gained increasing interest, for example, the reversible deformability found in vivo for the red blood cells (RBCs) plays an important role in blood rheology for vessels with diameters smaller than 300 μm, where the effective viscosity gets reduced due to RBCs migration to the vessel centre, resulting in the formation of a cell-free layer close to the vessels or microdevices walls [25][26][27][28][29] . These blood phenomena drive the development of particulate blood analogue fluids with similar properties and flow behaviour [19,30,31] . One of the main challenges in the development of these particulate fluids is the production of particles with the required mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Flexible PDMS microparticles to mimic RBCs in blood particulate analogue fluids

Pinho

Muñoz-Sánchez

Anes

et al. 2019

Mechanics Research Communications

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Polydimethylsiloxane (PDMS) has a wide variety of commercial and industrial applications due to its mechanical and rheological properties in a range similar to the living tissues. In this study, we demonstrate that PDMS can be used to produce deformable microparticles to be integrated in the development of particulate blood analogue fluids. The difficulties associated with the use of in vitro blood make it necessary to perform in vitro experiments of blood flow with blood analogue fluids. However, an ideal analogue must match the rheology of blood at several points, and for that, blood analogue fluids should be a suspension of microparticles with similar properties (size, shape and flexibility) to blood cells, in particular to the red blood cells (RBCs). The microparticles used in this study were produced from a transparent PDMS with crosslinking ratios of 10:1, 8:2 and 6:4; from a black PDMS with a ratio of 1:1 and from a red-pigmented PDMS. Each PDMS microparticles sample was suspended in Dextran 40 to perform deformability assays and cell-free layer analysis in a hyperbolic-shaped microchannel and steady shear viscosity measurements in a rheometer. The proposed microparticles suspensions show a great potential to mimic the structural and rheological properties of RBC suspensions and consequently to develop blood analogue fluids with rheological properties similar to real blood.

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Parallelization of Microfluidic Droplet Junctions for Ultraviscous Fluids

Kim

Cho

Baek

et al. 2022

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The parallelization of multiple microfluidic droplet junctions has been successfully achieved so that the production throughput of the uniform microemulsions/particles has witnessed considerable progress. However, these advancements have been observed only in the case of a low viscous fluid (viscosity of 10−2–10−3 Pa s). This study designs and fabricates a microfluidic device, enabling a uniform micro‐emulsification of an ultraviscous fluid (viscosity of 3.5 Pa s) with a throughput of ≈330 000 droplets per hour. Multiple T‐junctions of a dispersed oil phase, split from a single inlet, are connected into the single post‐crossflow channel of a continuous water phase. In the proposed device, the continuous water phase undergoes a series circuit, wherein the resistances are continuously accumulated. The independent corrugations of the dispersed oil phase channel, under the theoretical guidance, compromise such increased resistances; the ratio of water to oil flow rates at each junction becomes consistent across T‐junctions. Owing to the design being based on a fully 2D interconnection, single‐step soft lithography is sufficient for developing the full device. This easy‐to‐craft architecture contrasts with the previous approach, wherein complicated 3D interconnections of the multiple junctions are involved, thereby facilitating the rapid uptake of high throughput droplet microfluidics for experts and newcomers alike.

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PDMS droplet formation and characterization by hydrodynamic flow focusing technique in a PDMS square microchannel

Cited by 22 publications

References 32 publications

Production of gelatin microparticles in a flow focusing microfluidic device for biomedical applications

Production of gelatin microparticles in a flow focusing microfluidic device for biomedical applications

Flexible PDMS microparticles to mimic RBCs in blood particulate analogue fluids

Parallelization of Microfluidic Droplet Junctions for Ultraviscous Fluids

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