| 1. |
- Beech, Jason P., et al.
(author)
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Cell morphology and deformability in deterministic lateral displacement devices
- 2011
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In: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; 2, s. 1355-1357
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Conference paper (peer-reviewed)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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| 2. |
- Beech, Jason P., et al.
(author)
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Morphology-based sorting-blood cells and parasites
- 2010
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In: 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010. - 9781618390622 ; 2, s. 1343-1345
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Conference paper (peer-reviewed)abstract
- Morphology represents a hitherto unexploited source of specificity in microfluidic particle separation and may serve as the basis for label-free particle fractionation. There is a wealth of morphological changes in blood cells due to a wide range of clinical conditions, diseases, medication and other factors. Also, blood-borne parasites differ in morphology from blood cells. We present the use of Deterministic Lateral Displacement to create a chip-based, label-free diagnostic tool, capable of harvesting some of the wealth of information locked away in red blood cell morphology. We also use the device to separate the parasites that cause sleeping sickness from blood.
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| 3. |
- Beech, Jason P., et al.
(author)
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Sample preparation for single-cell whole chromosome analysis
- 2012
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In: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 998-999
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Conference paper (peer-reviewed)abstract
- In this work we present an integrated system for whole chromosome analysis of single bacterium. Using whole genome barcoding techniques, which offer direct and rapid microscopic visualization of the entire genome in one field-of-view, we aim to rapidly identify individual bacterium. We are developing our device to achieve the crucial, and difficult process of isolating a bacterium, removing the DNA in one piece and transferring it to a nano-channel for visualisation. In order to achieve control over the bacteria we encapsulate them in agarose, using flow focusing. The encapsulated bacteria can then be transported in microchannels to proximity with the nanochannels and then chemically lysis can be performed. Following lysis the intact genome can be extracted and transferred to the meandering nanochannel for analysis. We believe this device holds the potential to significantly decrease analysis times for single cell, whole genome analysis with the potential of opening up for automated, high-throughput genome analysis in microfluidic systems.
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| 4. |
- Beech, Jason, et al.
(author)
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Sorting cells by size, shape and deformability
- 2012
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In: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 12, s. 1048-1051
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Journal article (peer-reviewed)abstract
- While size has been widely used as a parameter in cellular separations, in this communication we show how shape and deformability, a mainly untapped source of specificity in preparative and analytical microfluidic devices can be measured and used to separate cells. © 2012 The Royal Society of Chemistry.
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| 5. |
- Emilsson, Gustav, 1989, et al.
(author)
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Identifying bacteria using DNA binding maps
- 2013
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In: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. - 9781632666246 ; 1, s. 473-475
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Conference paper (peer-reviewed)abstract
- We have developed an assay, based on nanofluidic channels and fluorescence microscopy, for optical mapping of DNA based on competitive binding between two molecules - one fluorescent and one sequence selective. From the experimental data we can extract binding constants for the two competing DNA binders, which may be subsequently used to calculate a theoretical reference map of any DNA with known sequence. The goal is to create a method for fast identification of bacteria from single DNA molecules without the need for additional cultivation or amplification. We here demonstrate a proof-of-principle experiment on phage DNA and furthermore show that the method can be used to distinguish between two strains of E. coli DNA and to map pieces of DNA onto the full genome.
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| 6. |
- Fritzsche, Joachim, 1977, et al.
(author)
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A lipid-based passivation scheme for nanofluidics
- 2012
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In: 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012; Okinawa; Japan; 28 October 2012 through 1 November 2012. - 9780979806452 ; , s. 1876-1878
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Conference paper (peer-reviewed)abstract
- Stretching DNA in nanochannels allows for direct, visual studies of genomic DNA at the single molecule level. In order to facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We show long-term passivation of nanochannel surfaces to several relevant reagents and demonstrate that the performance of the lipid bilayer is significantly better compared to standard bovine serum albumin-based passivation. Moreover, we demonstrate how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation.
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| 7. |
- Frykholm, Karolin, 1977, et al.
(author)
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Probing concentration-dependent behavior of DNA-binding proteins on a single-molecule level illustrated by Rad51
- 2013
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In: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 443:2, s. 261-268
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Journal article (peer-reviewed)abstract
- Low throughput is an inherent problem associated with most single-molecule biophysical techniques. We have developed a versatile tool for high-throughput analysis of DNA and DNA-binding molecules by combining microfluidic and dense DNA arrays. We use an easy-to-process microfluidic flow channel system in which dense DNA arrays are prepared for simultaneous imaging of large amounts of DNA molecules with single-molecule resolution. The Y-shaped microfluidic design, where the two inlet channels can be controlled separately and precisely, enables the creation of a concentration gradient across the microfluidic channel as well as rapid and repeated addition and removal of substances from the measurement region. A DNA array stained with the fluorescent DNA-binding dye YOYO-1 in a gradient manner illustrates the method and serves as a proof of concept. We have applied the method to studies of the repair protein Rad51 and could directly probe the concentration-dependent DNA-binding behavior of human Rad51 (HsRad51). In the low-concentration regime used (100 nM HsRad51 and below), we detected binding to double-stranded DNA (dsDNA) without positive cooperativity. (C) 2013 Elsevier Inc. All rights reserved.
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| 8. |
- Ghasemi, Masoomeh, et al.
(author)
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Separation of deformable hydrogel microparticles in deterministic lateral displacement devices
- 2012
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In: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 1672-1674
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Conference paper (peer-reviewed)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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| 9. |
- Holm, Stefan H., et al.
(author)
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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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In: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 530-532
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Conference paper (peer-reviewed)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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| 10. |
- Holm, Stefan H., et al.
(author)
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Combined density and size-based sorting in deterministic lateral displacement devices
- 2013
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In: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013. - 9781632666246 ; 2, s. 1224-1226
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Conference paper (peer-reviewed)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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