| 1. |
- Beech, Jason P., et al.
(författare)
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Active Posts in Deterministic Lateral Displacement Devices
- 2019
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Ingår i: Advanced Materials Technologies. - : Wiley. - 2365-709X. ; 4:9
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Tidskriftsartikel (refereegranskat)abstract
- Using electrically connected metal-coated posts in a deterministic lateral displacement (DLD) device and applying electric fields, electrokinetics is used to tune separations, significantly decrease the critical size for separation, and increase the dynamic range with switching times on the order of seconds. The strength of DLD stems from its binary behavior. To first approximation, particles move in one out of two trajectories based on their effective size. For particles that are close to the threshold size, a small external force is sufficient to nudge the particles from one trajectory to another. The devices consist of arrays of cylindrical metal-coated SU-8 posts connected by an underlying metal layer. This allows the application of voltages at the post surfaces and the generation of electric field gradients between neighboring posts, causing polarizable particles to experience a dielectrophoretic (DEP) force. This force, which depends on the volume and polarizability of the particle, can be made sufficient to push particles from one trajectory into another. In this way, the critical size in a device, normally fixed by the geometry, can be tuned. What's more, adding DEP in this way allows for the simultaneous creation of multiple size fractions.
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| 2. |
- Beech, Jason P., et al.
(författare)
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Electrokinetic wall effect mechanisms and applications
- 2020
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Ingår i: MicroTAS 2020 - 24th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9781733419017 ; , s. 42-43
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Konferensbidrag (refereegranskat)abstract
- Under the application of longitudinal electric fields in microchannels, microparticles experience lift forces that push them away from the channel walls and affect their trajectories. At high frequencies (>100KHz) the dielectrophoretic forces dominate and are well understood but at lower frequencies there is little agreement as to the exact nature of the forces, how they are generated and how they vary due to the many different experimental conditions that are used in microfluidics devices. Here we present an experimental study of these mechanisms.
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| 3. |
- Beech, Jason P., et al.
(författare)
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Separation of pathogenic bacteria by chain length
- 2018
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 1000, s. 223-231
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Tidskriftsartikel (refereegranskat)abstract
- Using Deterministic Lateral Displacement devices optimized for sensitivity to particle length, we separate subpopulations of bacteria depending on known properties that affect their capability to cause disease (virulence). For the human bacterial pathogen Streptococcus pneumoniae, bacterial chain length and the presence of a capsule are known virulence factors contributing to its ability to cause severe disease. Separation of cultured pneumococci into subpopulations based on morphological type (single cocci, diplococci and chains) will enable more detailed studies of the role they play in virulence. Moreover, we present separation of mixed populations of almost genetically identical encapsulated and non-encapsulated pneumococcal strains in our device.
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| 4. |
- Beech, Jason P., et al.
(författare)
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Sorting bacteria by chain length - A factor of virulence?
- 2016
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Ingår i: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016. - 9780979806490 ; , s. 250-251
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Konferensbidrag (refereegranskat)abstract
- Using Deterministic Lateral Displacement (DLD), we are able to separate bacteria by their size and their chain length. This separation enables the study of these properties as factors of virulence.
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| 5. |
- Beech, Jason P., et al.
(författare)
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The separation of nano-sized particles in micro-scaled post arrays
- 2019
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Ingår i: 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2019. - 9781733419000 ; , s. 10-11
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Konferensbidrag (refereegranskat)abstract
- The precise separation of nanoscale particles has proven challenging due to diffusion and the need to use nanoscale devices. We show the separation of particles in the 100 nm size range in Deterministic Lateral Displacement (DLD) devices with feature sizes in the 10 µm size range. We achieve this using Dielectrophoretic (DEP) forces, generated between the metal coated posts that act as active electrodes. This opens up for the separation of submicron particles based not only on size but also on electric and dielectric properties.
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| 6. |
- Beech, Jason P., et al.
(författare)
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Tunable separation and DNA manipulation in metal coated pillar arrays
- 2018
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Ingår i: 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018. - 9781510897571 ; 4, s. 2090-2093
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Konferensbidrag (refereegranskat)abstract
- Implementing electrically connected metal-coated posts in a Deterministic Lateral Displacement (DLD) device and applying electric fields, we use electrokinetics to achieve tunable particle separations and to trap and manipulate DNA. The strength of DLD stems from its typically binary behavior. Particles move in one out of two trajectories based on their effective size. For particles that are close to the threshold size, a minute external force is sufficient to nudge the particles from one trajectory to another. Dielectrophoresis (DEP) provides such a force and also gives specificity based on the dielectric properties of the particles.
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| 7. |
- Kim, Rebekah, et al.
(författare)
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DNA sample cleanup using deterministic lateral displacement
- 2016
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Ingår i: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016. - 9780979806490 ; , s. 1527-1528
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Konferensbidrag (refereegranskat)abstract
- Optical mapping relies on the preparation of fluorescent DNA. DNA must be imaged with good signal to noise and therefore the background of unwanted DNA fragments, fluorescent dyes and other reagents need to be removed. We use deterministic lateral displacement to separate 48.5 kbp DNA from < 10 kbp DNA. We also show the removal of 48.5 kbp DNA fragments from a background of fluorescent ATTO647N molecules and the recovery of >50 kbp molecules from a background of shorter digested fragments. In both cases improving signal to noise during imaging.
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| 8. |
- Tran, Si Hoai Trung, et al.
(författare)
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Sorting breast cancer cells based on deformability
- 2015
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Ingår i: MicroTAS 2015 - 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9780979806483 ; , s. 364-366
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Konferensbidrag (refereegranskat)abstract
- Due to their direct coupling to the physiology of the cells, the physical properties are especially attractive as markers for sorting and characterization of cancer cells. Where molecular surface markers are lacking, the physical properties can instead serve as inherent markers for separation. This is especially interesting for cancer cells where there are indications that soft cells are more metastatic than hard cells. Our work is expected to provide a deeper understanding of deformability based sorting based on deterministic lateral displacement (DLD). This will subsequently be used to optimize DLD devices for characterization and fractionation of cancer cells into subpopulations of different mechanical properties. Our aim is to develop a device to help oncologists gain more accurate prognoses and better monitoring of the effect of treatment.
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| 9. |
- Tran, Si Hoai Trung, et al.
(författare)
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Surface based fluidics for particle sorting
- 2015
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Ingår i: MicroTAS 2015 - 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9780979806483 ; , s. 2136-2137
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Konferensbidrag (refereegranskat)abstract
- We have created devices that are extremely simple to fabricate, function without pumps, are reusable and capable of dealing with very large differences in particle sizes without clogging. Our new approach to microfluidic particle sorting is precise enough for applications in blood fractionation, cancer cell sorting, parasite detection and sample decomplexing in general. We achieve this using Deterministic Lateral Displacement (DLD) in an open channel where particles flow across a patterned surface under the impetus of capillary forces alone.
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