Experimental and numerical study of elasto-inertial focusing in straight channels

Raoufi, Mohammad; Mashhadian, Ali; Niazmand, Hamid; Asadnia, Mohsen; Razmjou, Amir; Warkiani, Majid Ebrahimi

doi:10.1063/1.5093345

Cited by 47 publications

(43 citation statements)

References 54 publications

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“…When particle Re is much smaller than 1, viscous drag becomes dominant, and particles follow the streamline. Increasing particle Re augments inertial forces, causing inertial particle migration become obvious in the microchannel 49,50 . Particle migration within a straight channel strictly depends on its cross-section.…”

Section: Resultsmentioning

confidence: 99%

3D Printing of Inertial Microfluidic Devices

Bazaz

Rouhi

Raoufi

et al. 2020

Sci Rep

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143

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Inertial microfluidics has been broadly investigated, resulting in the development of various applications, mainly for particle or cell separation. Lateral migrations of these particles within a microchannel strictly depend on the channel design and its cross-section. Nonetheless, the fabrication of these microchannels is a continuous challenging issue for the microfluidic community, where the most studied channel cross-sections are limited to only rectangular and more recently trapezoidal microchannels. As a result, a huge amount of potential remains intact for other geometries with cross-sections difficult to fabricate with standard microfabrication techniques. In this study, by leveraging on benefits of additive manufacturing, we have proposed a new method for the fabrication of inertial microfluidic devices. In our proposed workflow, parts are first printed via a high-resolution DLP/SLA 3D printer and then bonded to a transparent PMMA sheet using a double-coated pressure-sensitive adhesive tape. Using this method, we have fabricated and tested a plethora of existing inertial microfluidic devices, whether in a single or multiplexed manner, such as straight, spiral, serpentine, curvilinear, and contraction-expansion arrays. Our characterizations using both particles and cells revealed that the produced chips could withstand a pressure up to 150 psi with minimum interference of the tape to the total functionality of the device and viability of cells. As a showcase of the versatility of our method, we have proposed a new spiral microchannel with right-angled triangular cross-section which is technically impossible to fabricate using the standard lithography. We are of the opinion that the method proposed in this study will open the door for more complex geometries with the bespoke passive internal flow. Furthermore, the proposed fabrication workflow can be adopted at the production level, enabling large-scale manufacturing of inertial microfluidic devices.

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Section: Resultsmentioning

confidence: 99%

3D Printing of Inertial Microfluidic Devices

Bazaz

Rouhi

Raoufi

et al. 2020

Sci Rep

Self Cite

143

View full text Add to dashboard Cite

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“…2). Since microfluidic channels with rectangular cross-sections are the most common, benefiting from soft-photolithography fabrication methods 141,142 , many researchers have probed particle migration dynamics in such channels 50,56,96,[101][102][103][143][144][145] . As the driving force due to fluid elasticity (elastic force F e ) is directed down the shear rate gradient 47 , particles are expected to migrate to the centerplane of a rectangular channel with an excessively low aspect ratio (AR, the ratio of cross-sectional height and width).…”

Section: Particle Migration In Inertialess Viscoelastic Flowsmentioning

confidence: 99%

Viscoelastic microfluidics: progress and challenges

2020

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The manipulation of cells and particles suspended in viscoelastic fluids in microchannels has drawn increasing attention, in part due to the ability for single-stream three-dimensional focusing in simple channel geometries. Improvement in the understanding of non-Newtonian effects on particle dynamics has led to expanding exploration of focusing and sorting particles and cells using viscoelastic microfluidics. Multiple factors, such as the driving forces arising from fluid elasticity and inertia, the effect of fluid rheology, the physical properties of particles and cells, and channel geometry, actively interact and compete together to govern the intricate migration behavior of particles and cells in microchannels. Here, we review the viscoelastic fluid physics and the hydrodynamic forces in such flows and identify three pairs of competing forces/effects that collectively govern viscoelastic migration. We discuss migration dynamics, focusing positions, numerical simulations, and recent progress in viscoelastic microfluidic applications as well as the remaining challenges. Finally, we hope that an improved understanding of viscoelastic flows in microfluidics can lead to increased sophistication of microfluidic platforms in clinical diagnostics and biomedical research.

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“…Apart from the experimental studies, several numerical studies were carried out to evaluate particle behavior in microchannels with various cross-sections under Newtonian or non-Newtonian fluid flow. Modeling particle fluid interactions using a direct numerical simulation (DNS) method, Raoufi et al studied the effect of the channel geometry and corner angle on particle focusing in viscoelastic solutions [19]. Additionally, numerical simulations were conducted on viscoelastic fluid flows in straight ducts with different cross-sections, allowing the origin of secondary flows and the influence of material parameters and the geometrical configuration of the flow passage to be numerically investigated [20].…”

Section: Introductionmentioning

confidence: 99%

Particle Focusing under Newtonian and Viscoelastic Flow in a Straight Rhombic Microchannel

Kwon

Kim

et al. 2020

Micromachines

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Particle behavior in viscoelastic fluids has attracted considerable attention in recent years. In viscoelastic fluids, as opposed to Newtonian fluids, particle focusing can be simply realized in a microchannel without any external forces or complex structures. In this study, a polydimethylsiloxane (PDMS) microchannel with a rhombic cross-sectional shape was fabricated to experimentally investigate the behavior of inertial and elasto-inertial particles. Particle migration and behavior in Newtonian and non-Newtonian fluids were compared with respect to the flow rate and particle size to investigate their effect on the particle focusing position and focusing width. The PDMS rhombic microchannel was fabricated using basic microelectromechanical systems (MEMS) processes. The experimental results showed that single-line particle focusing was formed along the centerline of the microchannel in the non-Newtonian fluid, unlike the double-line particle focusing in the Newtonian fluid over a wide range of flow rates. Numerical simulation using the same flow conditions as in the experiments revealed that the particles suspended in the channel tend to drift toward the center of the channel owing to the negative net force throughout the cross-sectional area. This supports the experimental observation that the viscoelastic fluid in the rhombic microchannel significantly influences particle migration toward the channel center without any external force owing to coupling between the inertia and elasticity.

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Experimental and numerical study of elasto-inertial focusing in straight channels

Cited by 47 publications

References 54 publications

3D Printing of Inertial Microfluidic Devices

3D Printing of Inertial Microfluidic Devices

Viscoelastic microfluidics: progress and challenges

Particle Focusing under Newtonian and Viscoelastic Flow in a Straight Rhombic Microchannel

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