| 1. |
- Barrett, Michael P., et al.
(författare)
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Microfluidics-based approaches to the isolation of African trypanosomes
- 2017
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Ingår i: Pathogens. - : MDPI AG. - 2076-0817. ; 6:4
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Forskningsöversikt (refereegranskat)abstract
- African trypanosomes are responsible for significant levels of disease in both humans and animals. The protozoan parasites are free-living flagellates, usually transmitted by arthropod vectors, including the tsetse fly. In the mammalian host they live in the bloodstream and, in the case of human-infectious species, later invade the central nervous system. Diagnosis of the disease requires the positive identification of parasites in the bloodstream. This can be particularly challenging where parasite numbers are low, as is often the case in peripheral blood. Enriching parasites from body fluids is an important part of the diagnostic pathway. As more is learned about the physicochemical properties of trypanosomes, this information can be exploited through use of different microfluidic-based approaches to isolate the parasites from blood or other fluids. Here, we discuss recent advances in the use of microfluidics to separate trypanosomes from blood and to isolate single trypanosomes for analyses including drug screening.
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| 2. |
- Beech, Jason P., et al.
(författare)
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Cell morphology and deformability in deterministic lateral displacement devices
- 2011
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Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; 2, s. 1355-1357
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Konferensbidrag (refereegranskat)abstract
- Deterministic Lateral Displacement (DLD) devices have been used to separate particles based on size [1] and shape [2]. Here we show how DLD devices can also be used to separate particles based on their ability to deform under shear forces. Varying experimental conditions allows us to vary the relative contributions of size, morphology and deformability. The ability to distinguish between cells based on deformability with high resolution and throughput, in cheap and simple devices, could find highly interesting and relevant applications, for example in the detection of circulating tumor cells or malaria-infected blood cells.
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| 3. |
- Ghasemi, Masoomeh, et al.
(författare)
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Separation of deformable hydrogel microparticles in deterministic lateral displacement devices
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 1672-1674
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Konferensbidrag (refereegranskat)abstract
- To better understand how deformable and non-spherical particles behave in sorting devices based on deterministic lateral displacement we generate models of biological particles with tunable size, shape and mechanical properties using stop-flow lithography and we explore how these parameters play a role in our separation devices. Hollow and solid cylinders are compared with respect to their deformability and their overall behavior in the device. Future work will expand the approach to a range of particle shapes and to particles with varied hydrogel composition to independently control the mechanical properties of the material.
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| 4. |
- Henry, Ewan, et al.
(författare)
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Sorting cells by their dynamical properties
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in cell sorting aim at the development of novel methods that are sensitive to various mechanical properties of cells. Microfluidic technologies have a great potential for cell sorting; however, the design of many micro-devices is based on theories developed for rigid spherical particles with size as a separation parameter. Clearly, most bioparticles are non-spherical and deformable and therefore exhibit a much more intricate behavior in fluid flow than rigid spheres. Here, we demonstrate the use of cells' mechanical and dynamical properties as biomarkers for separation by employing a combination of mesoscale hydrodynamic simulations and microfluidic experiments. The dynamic behavior of red blood cells (RBCs) within deterministic lateral displacement (DLD) devices is investigated for different device geometries and viscosity contrasts between the intra-cellular fluid and suspending medium. We find that the viscosity contrast and associated cell dynamics clearly determine the RBC trajectory through a DLD device. Simulation results compare well to experiments and provide new insights into the physical mechanisms which govern the sorting of non-spherical and deformable cells in DLD devices. Finally, we discuss the implications of cell dynamics for sorting schemes based on properties other than cell size, such as mechanics and morphology.
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| 5. |
- Holm, Stefan H., et al.
(författare)
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A high-throughput deterministic lateral displacement device for rapid and sensitive field-diagnosis of sleeping sickness
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 530-532
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Konferensbidrag (refereegranskat)abstract
- We present a simple and rapid microfluidic device capable of extracting and concentrating the parasite causing the fatal disease sleeping sickness (SS) from blood. The device is based on deterministic lateral displacement (DLD) and constructed with a single inlet with flow induced by an ordinary syringe. The simplicity is crucial as the device is intended for use in the resource depraved areas where the disease is endemic. With only one inlet an intricate design with multiple depths has been utilized to create a cell free stream from the blood plasma into which the parasites are forced and subsequently collected in a detection region. In order to maximize the sample volume up to 10 device layers were stacked on top of each other which resulted in a throughput of ∼10 μL/min. This allowed for an approximate time per test of below 15 min.
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| 6. |
- Holm, Stefan H., et al.
(författare)
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Combined density and size-based sorting in deterministic lateral displacement devices
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013. - 9781632666246 ; 2, s. 1224-1226
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Konferensbidrag (refereegranskat)abstract
- We present a deterministic-lateral-displacement (DLD) device that extends the capabilities of this traditionally sizebased particle separation technique to also be sensitive to density. By the use of T-shaped posts instead of the normally cylindrical posts the particle trajectory through the device will be a function of its vertical position which in turn is determined by the buoyancy of the particles. The potential lies in fast sorting of complex biological samples together with diagnosis and treatment-monitoring of diseases affecting cell-density, eg. cancer, sickle-cell anemia and malaria. We demonstrate proof-of-principle of combined size-and-density-based sorting, specifically particles of identical size but different density.
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| 7. |
- Holm, Stefan H., et al.
(författare)
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Density-based particle fractionation
- 2014
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Ingår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014. - 9780979806476 ; , s. 288-290
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Konferensbidrag (refereegranskat)abstract
- We present a label-free method capable of rapidly sorting particles based on their densities. Our device relies on deterministic lateral displacement (DLD) and achieves density fractionation by the use of T-shaped posts. By combining it with a lateral density gradient we achieve a density separation that is independent of size within a range given by the device geometry. Herein we present a proof-of-principle method which, in comparison to traditional density-separation techniques, is suitable for lab-on-a-chip environment.
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| 8. |
- Holm, Stefan H., et al.
(författare)
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Microfluidic Particle Sorting in Concentrated Erythrocyte Suspensions
- 2019
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Ingår i: Physical Review Applied. - 2331-7019. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- An important step in diagnostics is the isolation of specific cells and microorganisms of interest from blood. Since such bioparticles are often present at very low concentrations, throughput needs to be as high as possible. In addition, to ensure simplicity, a minimum of sample preparation is important. Therefore, sorting schemes that function for whole blood are highly desirable. Deterministic lateral displacement (DLD) devices have proven to be very precise and versatile in terms of a wide range of sorting parameters. To better understand how DLD devices perform for blood as the hematocrit increases, we carry out measurements and simulations for spherical particles in the micrometer range which move through DLD arrays for different flow velocities and hematocrits ranging from pure buffer to concentrated erythrocyte suspensions mimicking whole blood. We find that the separation function of the DLD array is sustained even though the blood cells introduce a shift in the trajectories and a significant dispersion for particles whose diameters are close to the critical size in the device. Simulations qualitatively replicate our experimental observations and help us identify fundamental mechanisms for the effect of hematocrit on the performance of the DLD device.
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| 9. |
- Holm, Stefan H., et al.
(författare)
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Multiple depths in a deterministic lateral displacement device for field-diagnosis of sleeping-sickness
- 2011
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Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; 1, s. 527-529
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Konferensbidrag (refereegranskat)abstract
- We present a simple and inexpensive device capable of extracting and concentrating the parasite causing sleeping sickness from blood. The device is aimed at being used in rural resource depraved areas where the disease is endemic; therefore simplicity is of paramount importance. The device is based on deterministic lateral displacement with a single inlet and flow induced by a syringe. Through an intricate design with multiple depths, a cell free stream is created from the blood plasma into which the parasites are guided and subsequently collected in a dedicated reservoir for observation.
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| 10. |
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