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| 2. |
- Andersson Svahn, Helene, et al.
(författare)
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Single cells or large populations?
- 2007
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 7:5, s. 544-546
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Barkefors, Irmeli, et al.
(författare)
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A fluidic device to study directional angiogenesis in complex tissue and organ culture models
- 2009
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 9:4, s. 529-535
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Tidskriftsartikel (refereegranskat)abstract
- Many signals that induce angiogenesis have been identified; however, it is still not clear how these signals interact to shape the vascular system. We have developed a fluidic device for generation of molecular gradients in 3-dimensional cultures of complex tissues and organs in order to create an assay for precise induction and guidance of growing blood vessels. The device features a centrally placed culture chamber, flanked by channels attached to a perfusion system used to generate gradients. A separate network of vacuum channels permits reversible attachment of the device to a flat surface. We show that the fluidic device can be used to create growth factor gradients that induce directional angiogenesis in embryonic mouse kidneys and in clusters of differentiating stem cells. These results demonstrate that the device can be used to accurately manipulate complex morphogenetic processes with a high degree of experimental control.
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| 4. |
- Beech, Jason, et al.
(författare)
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Tipping the balance of deterministic lateral displacement devices using dielectrophoresis.
- 2009
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 9:18, s. 2698-2706
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Tidskriftsartikel (refereegranskat)abstract
- We report the use of dielectrophoresis (DEP) to achieve tunability, improve dynamic range and open up for the separation of particles with regard to parameters other than hydrodynamic size in deterministic lateral displacement (DLD) devices. DLD devices have been shown capable of rapidly and continuously separating micrometer sized plastic spheres by size with a resolution of 20 nm in diameter and of being able to handle the separation of biological samples as wide ranging as bacterial artificial chromosomes and blood cells. DEP, while not exhibiting the same resolution in size separation as DLD, has the benefit of being easy to tune and can, by choosing the frequency, be used to probe a variety of particle properties. By combining DLD and DEP we open up for the advantages, while avoiding the drawbacks, of the two techniques. We present a proof of principle in which the critical size for separation of polystyrene beads is tuned in the range 2-6 microm in a single device by the application of moderate (100 V cm(-1)), low frequency (100 Hz) AC electric fields. The behaviour of the device was further investigated by performing simulations of particle trajectories, the results of which were in good qualitative agreement with experiments, indicating the potential of the method for tunable, high-resolution separations with respect to both size and polarisability.
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| 5. |
- Beech, Jason, et al.
(författare)
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Tuneable separation in elastomeric microfluidics devices.
- 2008
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 8:5, s. 657-659
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Tidskriftsartikel (refereegranskat)abstract
- We describe how the elastomeric properties of PDMS (polydimethylsiloxane) can be utilised to achieve tuneable particle separation in Deterministic Lateral Displacement devices via strain controlled alteration of inter-obstacle distances, a development that opens up new avenues toward more effective separation of particles in microfluidics devices.
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| 6. |
- Bridle, Helen, 1979, et al.
(författare)
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On-chip fabrication to add temperature control to a microfluidic solution exchange system
- 2008
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Ingår i: Lab on a Chip - Miniaturisation for Chemistry and Biology. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 8:3, s. 480-483
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Tidskriftsartikel (refereegranskat)abstract
- We present a concept for the post production modification of commercially available microfluidic devices to incorporate local temperature control, thus allowing for the exact alignment of heating structures with the existing features, e.g. wells, channels or valves, of a system. Specifically, we demonstrate the application of programmable local heating, controlled by computerized PI regulation, to a rapid solution exchanger. Characterisation of the system to show that both uniform temperature distributions and temperature gradients can be established, and to confirm that the solution exchange properties are undisturbed by heating, was achieved using in situ thermometry and amperometry. © The Royal Society of Chemistry.
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| 7. |
- Eriksson, Emma, 1980, et al.
(författare)
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A microfluidic system in combination with optical tweezers for analyzing rapid and reversible cytological alterations in single cells upon environmental changes
- 2007
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Ingår i: Lab on a chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 7:1, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- We report on the development of an experimental platform where epi-fluorescence microscopy and optical tweezers are combined with a microfluidic system to enable the analysis of rapid cytological responses in single cells. The microfluidic system allows two different media to be merged in a Y-shaped channel. Microscale channel dimensions ensure purely laminar flow and, as a result, an environmental gradient can be created between the two media. Optical tweezers are used to move a single trapped cell repeatedly between the different environments. The cell is monitored continuously by fluorescence microscopy during the experiment. In a first experiment on yeast (Saccharomyces cerevisiae) we observed changes in cell volume as the cell was moved between environments with different osmolarity. This demonstrated that the platform allowed analysis of cytological alterations on a time scale shorter than 0.2 s. In a second experiment we observed the spatial migration of the Yap1p transcription factor fused to GFP as a cell was moved from an environment of low to high oxidative capacity. The system is universal allowing the response to numerous environmental changes to be studied on the sub second time scale in a variety of model cells. We intend to use the platform to study how the age of cells, their progression through the cell cycle, or their genetic landscape, alter their capacity (kinetics and amplitude) to respond to environmental changes.
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| 8. |
- Frisk, Thomas, et al.
(författare)
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A micromachined interface for airborne sample-to-liquid transfer and its application in a biosensor system
- 2006
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Ingår i: Lab on a Chip. - : RSC Publishing. - 1473-0197 .- 1473-0189. ; 6:12, s. 1504-1509
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Tidskriftsartikel (refereegranskat)abstract
- A novel micromachined interface for airborne sample-to-liquid adsorption and droplet-to-liquid transfer was designed and fabricated. It enables a robust sheet liquid flow serving as an adsorption site. The interface was characterised for flow and pressure properties and tested successfully for the transfer/adsorption of different samples. A qualitative theoretical model of the device characteristics is presented. We also used the interface to introduce a novel method and system for fast detection of dust- and vapour-based narcotics and explosives traces. The microfluidic vapour-to-liquid adsorption interface was coupled to a set of downstream QCM sensors. The system was tested successfully, with 50 ng cocaine samples rendering 15 Hz frequency shifts and with 100 ng heroine samples rendering 50 Hz frequency shifts. Gravitation invariance of the open liquid interface was demonstrated successfully, with the interface mounted upside down as well as vertically. The detection time was reduced to half of the time needed in previous systems. Machine size, weight and cost were reduced.
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| 9. |
- Frisk, Thomas, et al.
(författare)
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An integrated QCM-based narcotics sensing microsystem
- 2008
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Ingår i: Lab on a Chip. - : RSC Publishing. - 1473-0197 .- 1473-0189. ; 8:10, s. 1648-1657
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Tidskriftsartikel (refereegranskat)abstract
- We present the design, fabrication and successful testing of a 14 x 14 x 4 mm(3) integrated electronic narcotics sensing system which consists of only four parts. The microsystem absorbs airborne narcotics molecules and performs a liquid assay using an integrated quartz crystal microbalance (QCM). A vertically conductive double-sided adhesive foil (VCAF) was used and studied as a novel material for LOC and MEMS applications and provides easy assembly, electrical contacting and liquid containment. The system was tested for measuring cocaine and ecstasy, with successful detection of amounts as small as 100 ng and 200 ng, respectively These levels are of interest in security activities in customs, prisons and by the police.
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| 10. |
- Gamby, Jean, et al.
(författare)
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Polycarbonate microchannel network with carpet of Gold NanoWires as SERS-active device
- 2009
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 9:12, s. 1806-1808
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Tidskriftsartikel (refereegranskat)abstract
- A polycarbonate (PC) microchannel network supporting gold nanowires was developed to be a SERS-active microchip. Observations of large increases in a Raman cross-section, allowed us to collect vibrational signatures which are not easily detectable by Raman techniques due to the high fluorescence level of bare PC. Compared to other SERS experiments, this study relies on the use of dielectric polymer/metal surfaces which are well defined at microscale and nanoscale levels. This device seems a promising tool for sensing the adsorption of biomolecules.
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