| 1. |
- Alizadehheidari, Mohammadreza, 1987, et al.
(författare)
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Nanoconfined circular DNA
- 2014
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Ingår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014. - 9780979806476 ; , s. 1353-1355
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Konferensbidrag (refereegranskat)abstract
- Studies of nanoconfined circular DNA are of interest both from a biological as well as a fundamental polymer physics perspective. We here present the use of nanofluidic channels as a tool for comparing statics and dynamics of the linear and circular configuration of the same DNA molecule.
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| 2. |
- Beech, J. P., et al.
(författare)
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What do photons do to fluorescently stained DNA in confinement?
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. ; 1, s. 5-7
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Konferensbidrag (refereegranskat)abstract
- We have studied a selection of factors influencing the damage of DNA in nanochannels during fluorescence imaging. For cutting and nicking of DNA we show that the DNA is shortened during imaging. To avoid photodamage over the course of several hours of a typical experiment, we demonstrate the importance of an oxygen free gas to propel the buffer solution through the device. Finally, by varying the size of the channels, we show indications that higher DNA concentrations lead to higher rates of photodamage necessitating a balance between needs for highly stretched DNA and needs for long measurement times.
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| 3. |
- Bilenberg, B., et al.
(författare)
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High resolution 100kV electron beam lithography in SU-8
- 2006
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317. ; 83:4-9, s. 1609-1612
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Tidskriftsartikel (refereegranskat)abstract
- High resolution 100 kV electron beam lithography in thin layers of the negative resist SU-8 is demonstrated. Sub-30 nm lines with a pitch down to 300 nm are written in 100 nm thick SU-8. Two reactive ion etch processes are developed in order to transfer the SU-8 structures into a silicon substrate, a Soft O-2-Plasma process to remove SU-8 residues on the silicon surface after development and a highly anisotropic SF6/O-2/CHF3 based process to transfer the pattern into a silicon substrate, with selectivity between silicon and SU-8 of approximately 2. 30 nm lines patterned in SU-8 are successfully transferred into a silicon substrate, which is used as a stamp in a nanoimprint lithography process to fabricate a nanochannel device for DNA stretching experiments. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Darnton, N., et al.
(författare)
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Hydrodynamics in 2 1/2 dimensions : Making jets in a plane
- 2001
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 13:21, s. 4891-4902
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Tidskriftsartikel (refereegranskat)abstract
- We show that a careful analysis of the Navier-Stokes equation in the low Reynolds number limit has two distinct solutions, one valid for a deep, thin curtain of flow and the other for a thin wide flow. We derive a solution to the latter situation and use the results to develop a new way to control fluid flows in thin, wide sheet flow.
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| 5. |
- Freitag, C., et al.
(författare)
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Meandering nanochannels for imaging of ultra-long DNA molecules
- 2011
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Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; 3, s. 1758-1760
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Konferensbidrag (refereegranskat)abstract
- A new chip design for handling and studying chromosomal DNA is described. Folding the nanochannels enables us to image an entire yeast chromosome in a single field of view. Together with existing mapping techniques our new design opens up the possibility of directly analyzing entire chromosomes in a single field of view using fluorescence microscopy. This would enable, for example, identification of microorganisms on a single-cell basis and the complete physical mapping of the human genome, chromosome by chromosome.
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| 6. |
- Henry, Ewan, et al.
(författare)
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Sorting red blood cells by their dynamical properties
- 2016
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Ingår i: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016. - 9780979806490 ; , s. 786-787
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Konferensbidrag (refereegranskat)abstract
- A combination of mesoscale hydrodynamic simulations and microfluidic experiments are used to explore the use of cells' mechanical and dynamical properties as biomarkers for separation. Dynamic behaviour of red blood cells (RBCs) within deterministic lateral displacement (DLD) devices is investigated within various array geometries and for different viscosity contrasts between the intra- and extra-cellular fluid. We find that the viscosity contrast and associated cell dynamics clearly determine RBC trajectories through DLD devices. 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.
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| 7. |
- Holm, S. H., et al.
(författare)
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Simplifying microfluidic separation devices towards field-detection of blood parasites
- 2016
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Ingår i: Analytical Methods. - : Royal Society of Chemistry (RSC). - 1759-9660 .- 1759-9679. ; 8:16, s. 3291-3300
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Tidskriftsartikel (refereegranskat)abstract
- With our sights set on a simple and inexpensive diagnostics device based on extraction and enrichment of parasites from human blood, we present a device design that relies on a combination of multiple different deterministic lateral displacement arrays. Our end goal is a microfluidic device that will be easy to use in the rural, resource-deprived areas where simple-to-use medical tools are crucially needed for rapid and accurate diagnosis. Here, we exemplify this in the application of blood parasite enrichment from a sample of blood. With trypanosomes as a model system we show a combination of functionalities designed into a single device based on several deterministic lateral displacement arrays of different depths arranged in series. With only one inlet and no expensive or complicated pumping mechanisms to run separations we ensure the level of simplicity necessary for field use.
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| 8. |
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| 9. |
- Lundberg, F., et al.
(författare)
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Protein depositions on one hydrocephalus shunt and on fifteen temporary ventricular catheters
- 1997
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Ingår i: Acta Neurochirurgica. - 0001-6268. ; 139:8, s. 734-742
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Tidskriftsartikel (refereegranskat)abstract
- Biomaterials are commonly used in modern medicine. Proteins are adsorbed to the surface of the biomaterial immediately after insertion. This report demonstrates the presence of adsorbed proteins in one infected cerebrospinal shunt from a child with hydrocephalus and on fifteen temporary ventricular catheters from adult patients with spontaneous or traumatic brain injuries. Depositions of vitronectin, fibrinogen and thrombospondin-fibronectin to some extent - on the shunt surface was imaged by field-emission scanning electron microscopy. Vitronectin, fibronectin, fibrinogen, and thrombospondin on the ventricular catheters were shown with radio-actively labelled antibodies. Furthermore, protein adsorption from human cerebrospinal fluid to heparinized and unheparinized polymers was studied under flowing conditions in vitro. On heparinized polymer, significantly reduced levels of vitronectin, fibronectin, and thrombospondin were exposed, as measured after 4 hours in vitro perfusion. After 24 hours perfusion, the differences in protein exposition between heparinized and unheparinized polymers were substantially reduced.
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| 10. |
- Montelius, L., et al.
(författare)
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Direct observation of the tip shape in scanning probe microscopy
- 1993
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 62:21, s. 2628-2630
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Tidskriftsartikel (refereegranskat)abstract
- In this study we report on the first direct observation of the real shape of the atomic force microscopy (AFM) tip using the AFM technique itself, utilizing a specially designed sample geometry. This is the first report of the so-called inverse AFM mode in which the tip is actually used as the sample and vice versa. We propose how this method can, with a very high accuracy, be used for studying objects, e.g., biomolecules, that are attached to the usual AFM cantilever tip. Finally, we discuss how this method can significantly increase the reliability of the obtained AFM images.
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