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| 2. |
- 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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| 3. |
- Robinson, Linda, 1975-, et al.
(författare)
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Electrochemical wettability switches gate aqueous liquids in microfluidic systems
- 2006
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 6, s. 1277-1278
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a simple low-voltage technique for gating the flow of aqueous liquids in microfluidic systems employing the electrochemically-controlled surface energy of the conjugated polymer poly(3-hexylthiophene).
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| 4. |
- Stangegaard, M., et al.
(författare)
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A biocompatible micro cell culture chamber (microCCC) for the culturing and on-line monitoring of eukaryote cells
- 2006
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Ingår i: Lab on a Chip - Miniaturisation for Chemistry and Biology. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 6:8, s. 1045-1051
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that a polymeric (PMMA) chip with medium perfusion and integrated heat regulation provides sufficiently precise heat regulation, pH-control and medium exchange to support cell growth for weeks. However, it was unclear how closely the cells cultured in the chip resembled cells cultured in the culture flask. In the current study, gene expression profiles of cells cultured in the chip were compared with gene expression profiles of cells cultured in culture flasks. The results showed that there were only two genes that were differently expressed in cells grown in the cell culture chip compared to cell culture flasks. The cell culture chip could without further modification support cell growth of two other cell lines. Light coming from the microscope lamp during optical recordings of the cells was the only external factor identified, that could have a negative effect on cell survival. Low grade light exposure was however compatible with optical recordings as well as cell viability. These results strongly indicate that a cell culture chip could be constructed that allowed for on-line optical recording of cellular events without affecting the cell culturing condition compared to cell cultured in culture flasks incubated in a dark and CO 2 conditioned incubator. © The Royal Society of Chemistry 2006.
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| 5. |
- Wiklund, Martin, et al.
(författare)
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Ultrasonic enhancement of bead-based bioaffinity assays
- 2006
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 6:10, s. 1279-1292
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Forskningsöversikt (refereegranskat)abstract
- Ultrasonic radiation forces can be used for non-intrusive manipulation and concentration of suspended micrometer-sized particles. For bioanalytical purposes, standing-wave ultrasound has long been used for rapid immuno-agglutination of functionalized latex beads. More recently, detection methods based on laser-scanning fluorometry and single-step homogeneous bead-based assays show promise for fast, easy and sensitive biochemical analysis. If such methods are combined with ultrasonic enhancement, detection limits in the femtomolar region are feasible. In this paper, we review the development of standing-wave ultrasonic manipulation for bioanalysis, with special emphasis on miniaturization and ultrasensitive bead-based immunoassays.
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| 6. |
- Wiklund, Martin, et al.
(författare)
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Ultrasonic standing wave manipulation technology integrated into a dielectrophoretic chip
- 2006
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 6:12, s. 1537-1544
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Tidskriftsartikel (refereegranskat)abstract
- Several cell-based biological applications in microfluidic systems require simultaneous high-throughput and individual handling of cells or other bioparticles. Available chip-based tools for contactless manipulation are designed for either high-precision handling of individual particles, or high-throughput handling of ensembles of particles. In order to simultaneously perform both, we have combined two manipulation technologies based on ultrasonic standing waves (USWs) and dielectrophoresis (DEP) in a microfluidic chip. The principle is based on the competition between long-range ultrasonic forces, short-range dielcctrophoretic forces and viscous drag forces from the fluid flow. The ultrasound is coupled into the microchannel resonator by an external transducer with a refractive element placed on top of the chip, thereby allowing transmission light microscopy to continuously monitor the biological process. The DEP manipulation is generated by an electric field between co-planar microelectrodes placed on the bottom surface of the fluid channel. We demonstrate flexible and gentle elementary manipulation functions by the use of USWs and linear or curved DEP deflector elements that can be used in high-throughput biotechnology applications of individual cells.
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