| 1. |
- Aljadi, Zenib, et al.
(författare)
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Layer-by-Layer Cellulose Nanofibrils : A New Coating Strategy for Development and Characterization of Tumor Spheroids as a Model for In Vitro Anticancer Drug Screening
- 2022
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Ingår i: Macromolecular Bioscience. - : Wiley. - 1616-5187 .- 1616-5195. ; 22:10
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional multicellular spheroids (MCSs) are complex structure of cellular aggregates and cell-to-matrix interaction that emulates the in-vivo microenvironment. This research field has grown to develop and improve spheroid generation techniques. Here, we present a new platform for spheroid generation using Layer-by-Layer (LbL) technology. Layer-by-Layer (LbL) containing cellulose nanofibrils (CNF) assemble on a standard 96 well plate. Various bi-layer numbers, multiple cell seeding concentration, and two tumor cell lines (HEK 293 T, HCT 116) are utilized to generate and characterize spheroids. The number and proliferation of generated spheroids, the viability, and the response to the anti-cancer drug are examined. The spheroids are formed and proliferated on the LbL-CNF coated wells with no significant difference in connection to the number of LbL-CNF bi-layers; however, the number of formed spheroids correlates positively with the cell seeding concentration (122 ± 17) and (42 ± 8) for HCT 116 and HEK 293T respectively at 700 cells ml−1. The spheroids proliferate progressively up to (309, 663) µm of HCT 116 and HEK 293T respectively on 5 bi-layers coated wells with maintaining viability. The (HCT 116) spheroids react to the anti-cancer drug. We demonstrate a new (LbL-CNF) coating strategy for spheroids generation, with high performance and efficiency to test anti-cancer drugs.
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| 2. |
- Banerjee, Indradumna, et al.
(författare)
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Analog particle position tuning in Elasto-inertial microfluidic flows
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We observe for the first time an analog trend in particle focusing in a high throughput weakly viscoelastic regime, where it is possible to tune particles into multiple intermediate focusing positions that lie between the "Segre-Silberberg annulus" and the center of a circular microcapillary. The "Segre-Silberberg annulus" (0.6 times the pipe radius), that describes particle equilibrium in a predominantly inertial flow, shrinks consistently closer to the center for increasing elasticity in extremely dilute PEO concentrations (ranging from 0.001 wt% to 0.05wt%). The experimental observations are supported by direct numerical simulations, where an Immersed Boundary Method is used to account for the presence of particles and a FENE-P model is used to simulate the presence of polymers in a Non-Newtonian fluid. The numerical simulations study the dynamics and stability of finite size particles and are further used to analyze particle behavior at Reynolds number higher than what is allowed by the present experimental setup. In particular, we are able to report the entire migration trajectories of the particles as they reach their final equilibrium positions and extend our predictions to other geometries such as the square cross-section. We believe complex effects originate due to a combination of inertia and elasticity in a weakly viscoelastic regime, where neither inertia nor elasticity are able to mask each other's effect completely, thus leading to a number of intermediate focusing positions. The present study provides a new understanding into the mechanism of particle focusing in elasto-inertial flows and opens up new possibilities for exercising analog control in tuning the particle focusing positions.
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| 3. |
- Banerjee, Indradumna, et al.
(författare)
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Analogue tuning of particle focusing in elasto-inertial flow
- 2021
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Ingår i: Meccanica (Milano. Print). - : Springer Science and Business Media B.V.. - 0025-6455 .- 1572-9648. ; 56:7, s. 1739-1749
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Tidskriftsartikel (refereegranskat)abstract
- We report a unique tuneable analogue trend in particle focusing in the laminar and weak viscoelastic regime of elasto-inertial flows. We observe experimentally that particles in circular cross-section microchannels can be tuned to any focusing bandwidths that lie between the “Segre-Silberberg annulus” and the centre of a circular microcapillary. We use direct numerical simulations to investigate this phenomenon and to understand how minute amounts of elasticity affect the focussing of particles at increasing flow rates. An Immersed Boundary Method is used to account for the presence of the particles and a FENE-P model is used to simulate the presence of polymers in a Non-Newtonian fluid. The numerical simulations study the dynamics and stability of finite size particles and are further used to analyse the particle behaviour at Reynolds numbers higher than what is allowed by the experimental setup. In particular, we are able to report the entire migration trajectories of the particles as they reach their final focussing positions and extend our predictions to other geometries such as the square cross section. We believe complex effects originate due to a combination of inertia and elasticity in the weakly viscoelastic regime, where neither inertia nor elasticity are able to mask each other’s effect completely, leading to a number of intermediate focusing positions. The present study provides a fundamental new understanding of particle focusing in weakly elastic and strongly inertial flows, whose findings can be exploited for potentially multiple microfluidics-based biological sorting applications.
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| 4. |
- Banerjee, Indradumna, 1986-, et al.
(författare)
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Dynamics of Inertial migration of particles in straight channels
- 2017
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Konferensbidrag (refereegranskat)abstract
- SUMMARYWe study numerically the entire migration dynamics of spherical and oblate particles in straight rectangular and square cross sectional ducts. The reported results can help in design of straight duct channel based microfluidic systems. KEYWORDS: Inertial microfluidics, Lateral migration, Oblate particles, Straight particles. INTRODUCTIONWe simulate spherical and oblate rigid particles in straight ducts of different aspect ratios using an Immersed Boundary Method. To the best of our knowledge, this is the first time not only the equilibrium position of particles is described, but also the entire migration dynamics of the particle from the initial to final position, including particle trajectory, velocity, rotation and orientation, are investigated. EXPERIMENTAL The fluid is considered incompressible and its motion is governed by the Navier Stokes and Continuity equations. The numerical approach employed is an Immersed Boundary Method (IBM) with two sets of grid points: an equispaced Eulerian mesh for the fluid flow, and Lagrangian grid points uniformly distributed on the surface of the particle. The flow is set up in square and rectangular cross section ducts with no slip and no penetration boundary conditions (Fig.1). RESULTS AND DISCUSSIONWe examine the lateral motion of spherical and oblate particles using the IBM method mentioned above. While simulating three different spheres in a square duct of duct width to sphere diameter ratio H/Ds= [3.5, 5, 10], we find that the particles focus at closest face-cantered equilibrium position from their point of introduction(Fig.2a). We also show the downstream length needed for a sphere to focus, focusing length, as a function of the distance from the vertical duct symmetry line and as a function of Reynolds number(Fig.2b and c respectively). Spherical particles in rectangular duct tend to move laterally toward the longer length wall and then slowly moves towards the equilibrium position at the face-centre along the long wall(fig.3a). We also observe that the focusing length is longer for spherical particles in a rectangular duct, about three times longer than that in square duct (fig. 3b). In case of an oblate particle flowing through a square duct, the lateral motion towards the face centred equilibrium position is similar to that of a sphere (fig.4a), however there is significant tumbling motion of the particle as it tries to reach equilibrium(fig.4b).In a rectangular duct of aspect ratio 2, the oblate particle reaches a steady configuration on the duct symmetry line at the center of the different faces (fig.5a). The focusing length surprisingly is shorter in a rectangular duct for an oblate particle in contrast to its focusing length in a square duct. This is attributed to the higher lateral velocity of the oblate in the second stage of the migration, that with negligible tumbling(fig.5b). The behavior of three oblate particles in a square duct of duct width to longer diameter ratio H/Ds= [3.5, 5, 10] is different compared to a sphere as the largest oblate tend to focus at the duct cross section diagonals compared to the other two which are at face centred equilibrium as in case of a sphere(fig.6a). We attribute this to the rotation rate of the larger particle which is initially increasing and then decreasing(fig.6b).When it comes to focusing lengths, the smaller particles need longer times to reach their final equilibrium(fig.6c). Another interesting behavior we see is the effect of Reynolds number, where it can be seen that the oblate particles show a tilt of 21 degrees when focusing at equilibrium at certain high Reynolds number (fig.7). CONCLUSIONThe results presented employ a highly accurate interface-resolved numerical algorithm, based on the Immersed Boundary Method to study the entire inertial migration of an oblate particle in both square and rectangular ducts and compare it with that of a single sphere. Currently, we apply a volume penalization method and polymeric drag component to the code to solve for viscoelastic effects in circular microcapillaries. ACKNOWLEDGEMENTSThis work was supported by the European Research Council Grant no. ERC-2013-CoG-616186, TRITOS and by the Swedish Research Council Grant no. VR 2014-5001, COST Action MP1305: Flowing matter, and computation time from SNIC. REFERENCES : Lashgari, Iman, et al. Journal of Fluid Mechanics 819 (2017): 540-561.
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| 5. |
- Banerjee, Indradumna, et al.
(författare)
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Particle focusing dynamics in extended elasto inertial flow
- 2018
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Ingår i: 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018. - : Chemical and Biological Microsystems Society. - 9781510897571 ; , s. 472-475
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Konferensbidrag (refereegranskat)abstract
- We report the decoupled effects of inertial and viscous forces on particle focusing, the stability of particles, and particle trajectories to reach equilibrium position in an extended elasto inertial pressure driven flow, in a circular micro-capillary. We report numerically and experimentally for the first time, the existence of multiple stable equilibrium positions in the EEI regime, which was unobserved for flows previously studied at lower Reynolds number viscoelastic flows.
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| 6. |
- Etcheverry, Sebastian, et al.
(författare)
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All silica fibre microflow cytometer
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Flow cytometry is currently the gold standard for analysis of cells in the medical laboratory and biomedical research. Fuelled by the need of point-of-care diagnosis, a significant effort has been made to miniaturize and reduce cost of flow cytometers. However, despite recent advances, current microsystems remain less versatile and much slower than their large-scale counterparts. In this work, an all-silica fibre microflow cytometer is presented that measures fluorescence and scattering from particles and cells. It integrates cell transport in circular capillaries and light delivery by optical fibres Single-stream cell focusing is performed by Elasto-inertial microfluidics to guarantee optical accuracy and sensitivity. The capability of this technique is extended to high flow rates (up to 800 µl/min), enabling throughput of 2500 particles/s. The robust, portable and low-cost system described here could be the basis for a point-of-care flow cytometer with a performance comparable to commercial systems.
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| 7. |
- Etcheverry, Sebastián, et al.
(författare)
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High performance micro-flow cytometer based on optical fibres
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometry is currently the gold standard for analysis of cells in the medical laboratory and biomedical research. Fuelled by the need of point-of-care diagnosis, a significant effort has been made to miniaturize and reduce cost of flow cytometers. However, despite recent advances, current microsystems remain less versatile and much slower than their large-scale counterparts. In this work, an all-silica fibre microflow cytometer is presented that measures fluorescence and scattering from particles and cells. It integrates cell transport in circular capillaries and light delivery by optical fibres. Single-stream cell focusing is performed by Elasto-inertial microfluidics to guarantee accurate and sensitive detection. The capability of this technique is extended to high flow rates (up to 800 mu l/min), enabling a throughput of 2500 particles/s. The robust, portable and low-cost system described here could be the basis for a point-of-care flow cytometer with a performance comparable to commercial systems.
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| 8. |
- Harish, Achar Vasant, et al.
(författare)
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Fiber Based Optofluidic Micro-Flow Cytometer Collecting Side-Scattered Light
- 2020
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- A compact fiber capillary based microflow cytometer capable of detecting side-scattered-light is demonstrated by using a 45° angle-cleaved metal coated optical fiber tip.
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| 9. |
- Harish, Achar Vasant, et al.
(författare)
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Lab-in-a-fiber microfluidic cytometer for point-of-care biomedical diagnostics
- 2021
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Ingår i: Proceedings MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 261-262
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Konferensbidrag (refereegranskat)abstract
- We describe a prototype of an all-fiber microfluidic cytometer capable of analyzing particles ranging from 2-20 µm in diameter. The portable all-fiber cytometer is fabricated using different diameter silica capillaries for flow of microparticles and optical fibers to deliver and collect light. As a proof of concept, we analyze mixed population of beads of three different sizes and classify them with our all-fiber cytometer.
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| 10. |
- Harish, Achar Vasant, et al.
(författare)
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Optofluidic Fiber Component to Separate Micron-Sized Particles using Elasto-Inertial Focusing
- 2020
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - : Institute of Electrical and Electronics Engineers Inc..
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Konferensbidrag (refereegranskat)abstract
- Using various fiber capillaries with different diameters and multiple holes we develop an optofluidic component capable of separating micron-sized beads emulating cells and bacteria, exploiting particle focusing in a viscoelastic fluid and analyzed optically.
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