Computational inertial microfluidics: a review

Bazaz, Sajad Razavi; Mashhadian, Ali; Ehsani, Abbas; Saha, Suvash C.; Krüger, Timm; Warkiani, Majid Ebrahimi

doi:10.1039/c9lc01022j

Cited by 141 publications

(58 citation statements)

References 132 publications

(185 reference statements)

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“…In square straight microchannels (with an aspect ratio (AR) (width/height) of 1), particles migrate to four equilibrium positions located at the center of each wall. Changing the cross-section to rectangular disturbs this focusing pattern where in a rectangular straight microchannel with AR of 0.5, focusing positions reduce to two near the center of long walls 51 . This behavior was explained by Zhou and Papautsky where they identified two-stage particle migration in rectangular straight microchannels 21 .…”

Section: Resultsmentioning

confidence: 99%

3D Printing of Inertial Microfluidic Devices

Bazaz

Rouhi

Raoufi

et al. 2020

Sci Rep

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150

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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

150

View full text Add to dashboard Cite

show abstract

“…In certain Re, these equilibrium positions are parallel to each other and the adjacent walls [31,32]. Spontaneous lateral migration of particles in Poiseuille flow and finite channel Re arises from a balance between dominant lift forces (F L ), including shear-gradient-induced lift force (F S ), and wall induced lift force (F W ) which are orthogonal to the flow directions [33]. The schematic of inertial lift forces has been shown in Figure 1A.…”

Section: Design Principlementioning

confidence: 99%

High-Throughput Particle Concentration Using Complex Cross-Section Microchannels

et al. 2020

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High throughput particle/cell concentration is crucial for a wide variety of biomedical, clinical, and environmental applications. In this work, we have proposed a passive spiral microfluidic concentrator with a complex cross-sectional shape, i.e., a combination of rectangle and trapezoid, for high separation efficiency and a confinement ratio less than 0.07. Particle focusing in our microfluidic system was observed in a single, tight focusing line, in which higher particle concentration is possible, as compared with simple rectangular or trapezoidal cross-sections with similar flow area. The sharper focusing stems from the confinement of Dean vortices in the trapezoidal region of the complex cross-section. To quantify this effect, we introduce a new parameter, complex focusing number or CFN, which is indicative of the enhancement of inertial focusing of particles in these channels. Three spiral microchannels with various widths of 400 µm, 500 µm, and 600 µm, with the corresponding CFNs of 4.3, 4.5, and 6, respectively, were used. The device with the total width of 600 µm was shown to have a separation efficiency of ~98%, and by recirculating, the output concentration of the sample was 500 times higher than the initial input. Finally, the investigation of results showed that the magnitude of CFN relies entirely on the microchannel geometry, and it is independent of the overall width of the channel cross-section. We envision that this concept of particle focusing through complex cross-sections will prove useful in paving the way towards more efficient inertial microfluidic devices.

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“…[17] Vortexes will form when the Reynolds number (Re)ofthe flow reaches ahigh value (Re > 20), which is also termed as inertia flows. [18,19] In other words, these vortexes will not form in low Reynolds number flow regime (Re < 1) named Stokes flow or creeping flow. [20] However,i tn eeds av ery high flow speed to achieve high Reynolds number in am icro-channel.…”

Section: Introductionmentioning

confidence: 99%

“…Some efforts have been made to create the vortex flow in Stokes flow regime by applying an external force.A coustic method, [12,13,23,24] electroosmosis or alternating current electrohydrodynamic [25,26] have been used to create the vortex flow with the applications in enhancing mixing, single-cell trapping [18] and manipulation of deposition. [20] However,these methods rely on complex devices.I ti ss till ac hallenge to provide afeasible strategy to create the vortex flow in Stokes flow regime.…”

Section: Introductionmentioning

confidence: 99%

Evaporation Induced Spontaneous Micro‐Vortexes through Engineering of the Marangoni Flow

Cai

Huang

et al. 2020

Angew Chem Int Ed

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Vortex flow fields are widely used to manipulate objects at the microscale in microfluidics. Previous approaches to produce the vortex flow field mainly focused on inertia flows. It remains a challenge to create vortexes in Stokes flow regime. Here we reported an evaporation induced spontaneous vortex flow system in Stokes flow regime by engineering Marangoni flow in a micro‐structured microfluidic chip. The Marangoni flow is created by nonuniform evaporation of surfactant solution. Various vortexes are constructed by folding the air–water interface via microstructures. Patterns of vortexes are programmable by designing the geometry of the microstructures and are predictable using numerical simulations. Moreover, rotation of micro‐objects and enrichment of micro‐particles using vortex flow is demonstrated. This approach to create vortexes will provide a promising platform for various microfluidic applications such as biological analysis, chemical synthesis, and nanomaterial assembly.

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Computational inertial microfluidics: a review

Abstract: Schematic illustration of various kinds of geometries used for inertial microfluidics.

Cited by 141 publications

References 132 publications

3D Printing of Inertial Microfluidic Devices

3D Printing of Inertial Microfluidic Devices

High-Throughput Particle Concentration Using Complex Cross-Section Microchannels

Evaporation Induced Spontaneous Micro‐Vortexes through Engineering of the Marangoni Flow

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