Droplet formation in a flow focusing configuration: Effects of viscoelasticity

Nooranidoost, Mohammad; Izbassarov, Daulet; Muradoğlu, Metin

doi:10.1063/1.4971841

Cited by 47 publications

(26 citation statements)

References 38 publications

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“…The front-tracking method was introduced by Unverdi and Tryggvason 46 and has been successfully applied to study a wide range of interfacial flows as reviewed by Tryggvason et al 47,49 The method has been extended to treat viscoelastic effects and applied to study various multiphase flows. [50][51][52][53][54] In a front-tracking method, the field equations are solved on a regular structured staggered Eulerian grid using a projection method and the interface between different phase is tracked explicitly by a Lagrangian grid consisting of connected marker points 47 as shown in Fig. 2.…”

Section: Methodsmentioning

confidence: 99%

A computational study of droplet-based bioprinting: Effects of viscoelasticity

2019

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Section: Methodsmentioning

confidence: 99%

A computational study of droplet-based bioprinting: Effects of viscoelasticity

2019

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“…(3) and (4) are solved within the cell and viscoelastic shell fluid droplet, where the viscoelasticity appears. The viscoelastic convective term in viscoelastic model is treated by a fifth-order upwind WENO-Z scheme along with a log-conformation method to overcome high Weissenberg number to preserve the positive-definiteness of the conformation tensor 45,46 .…”

Section: Viscoelastic Liquid Droplet Model For Leukemia Cells the Cementioning

confidence: 99%

Improving viability of leukemia cells by tailoring shell fluid rheology in constricted microcapillary

Nooranidoost

Kumar

2020

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Encapsulated cell therapy has shown great potential in the treatment of several forms of cancer. Microencapsulation of these cancer cells can protect the core from the harmful effects of the neighboring cellular environment and can supply nutrients and oxygen. Such an encapsulation technique ensures cell viability and enables targeted drug delivery in cancer therapy. The cells immobilized with a biocompatible shell material can be isolated from the ambient and can move in constricted microcapillary. However, transportation of these cells through the narrow microcapillary may squeeze and mechanically damage the cells which threaten the cell viability. The cell type, conditions and the viscoelastic properties of the shell can dictate cell viability. A front-tracking numerical simulation shows that the engineered shell material with higher viscoelasticity improves the cell viability. It is also shown that low cortical tension of cells can contribute to lower cell viability. Cancer cell mechanics have been extensively studied in microfluidic systems for cell sorting 1 , cell banking 2 and cancer therapy 3. Several research papers have classified cancer cells based on their mechanical properties, which can be utilized for the development of innovative diagnostic devices 3-6. The cancer cell deformation has been studied as a tool to sort healthy and unhealthy cells for cancer therapies and to disrupt the metastatic process 3. Microfluidic optical stretchers can deliver individual cells 7. The experiments on malignant transformation of human breast epithelial cells characterized the relationship between cellular function and cytoskeletal mechanical properties. The cancer cells may deform up to five times more than the healthy cells and that the metastatic cancer cells have a tendency to deform more than the non-metastatic cancer cells 7. Encapsulation of various cancer cells has been done over long culture periods using tumor microsphere and spheroids models 2. This study showed a higher uniformity and lower variability in diameter and circularity of the tumor microspheres over self-aggregated tumor spheroids, however both models can assure high cell viability. A mathematical model also has been developed to characterize the cellular interaction with endothelium that showed a larger deformation of cancer cells compared to healthy cells during metastasis 5. Thus, while encapsulation techniques in microchannels improve cell viability and target delivery, it is important to study the deformation of encapsulated leukemia cells in constricted microchannels. Although numerous experiments have been conducted in cell biophysics, modeling simulations of cell mechanics in bio-microfluidic systems have been lacking largely due to the complexity of the system. Lykov et al. 8 reviewed recent modeling approaches for cell mechanics simulations. It is possible to develop computational models to study the flow phenomena for different suspended cells such as white blood cells (WBC), circulating tumor cells (CTC) and other cancer cells. T...

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“…Other factors such as elasticity, wall-adhesion, viscoelasticity, and bending elasticity of the droplet were neglected. 2,[18][19][20] ANALYTICAL METHOD…”

Section: Physical Model and Assumptionsmentioning

confidence: 99%

Pressure of a viscous droplet squeezing through a short circular constriction: An analytical model

et al. 2018

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The model of a droplet squeezed through a narrow-constricted channel has many applications in pathology, chip/filter/membrane design, drug delivery, etc. Understanding the transient physics of the squeezing process is important in the design and optimization of many micro flow systems. However, available models often ignore the influence of droplet viscosity, and they usually feature low numerical efficiency by solving Navier-Stokes equations. In the present research, we developed a low-dimension analytical model to predict the pressure of squeezing a viscous droplet through a circular constricted channel with acceptable fidelity and low computational cost. Our approach is as follows. We first adapt the Hagen-Poiseuille law to predict the viscosity effect of droplet squeezing. Next, we obtain an analytical expression for the extra pressure caused by only the curvature change obtained. Finally, the general expression of squeezing pressure taking consideration of viscosity and surface tension is expressed. The analytical model we developed is in great agreement with the numerical solutions of the Navier-Stokes equation at a low Reynolds number and low capillary number. These findings have fundamental significance for future applications in engineering and industry.

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Droplet formation in a flow focusing configuration: Effects of viscoelasticity

Cited by 47 publications

References 38 publications

A computational study of droplet-based bioprinting: Effects of viscoelasticity

A computational study of droplet-based bioprinting: Effects of viscoelasticity

Improving viability of leukemia cells by tailoring shell fluid rheology in constricted microcapillary

Pressure of a viscous droplet squeezing through a short circular constriction: An analytical model

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