| 1. |
- Evander, Mikael, et al.
(författare)
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Acoustic trapping efficiency of nanoparticles and bacteria
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 515-517
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a method to characterize the acoustic trapping efficiency of nanoparticles and bacteria when using seeding particles. Through the use of fluorescent microscopy and video analysis, single particles/bacteria were counted as they entered the acoustic trap at different flow focusing ratios and by comparing the amount of trapped objects to the amount of objects that were lost from the trap, the trapping efficiency could be calculated. Using fluorescent 780 nm polystyrene particles, an optimization of the hydrodynamic sample pre-focusing could be performed. For a flow focusing ratio of 1:10 or 5:6 (sample:sheath flow), a trapping efficiency of around 90% could be achieved at a total flow rate of 11 μl/min. At a flow focusing ratio of 1:10, GFP-producing E. coli could be trapped at an efficiency of above 95%. Using this characterization technique, important aspects of the acoustic trapping method (e.g. transducer frequency and voltage, size and type of seeding particle, amount of flow focusing, total flow rate etc.) can be characterized and optimized.
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| 2. |
- Ohlsson, Pelle, et al.
(författare)
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Acoustic separation of bacteria from blood cells at high cell concentrations enabled by acoustic impedance matched buffers
- 2014
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Ingår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014. - 9780979806476 ; , s. 388-390
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Konferensbidrag (refereegranskat)abstract
- We have developed a method to separate bacteria from red and white blood cells (henceforth collectively called blood cells) using acoustophoresis, for subsequent PCR detection. To maximize throughput, we have now investigated the effect of increased cell concentration on the separation. Increasing the blood concentration drastically decreases bacteria recovery, but we show that this can be remedied by optimizing the acoustic impedance of the center buffer. This way we can recover 89% of the bacteria while removing more than 99.8% of the blood cells from 1 ml whole blood within 25 min, paving the way for new sepsis diagnostics methods.
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| 3. |
- Ohlsson, Pelle, et al.
(författare)
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Microchip electroseparation of proteins using lipid-based nanoparticles
- 2010
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835. ; 31:22, s. 3696-3702
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Tidskriftsartikel (refereegranskat)abstract
- Porous liquid crystalline lipid-based nanoparticles are shown here to enable protein analysis in microchip electroseparation by reducing sample adsorption. Additionally, higher stability and reproducibility of the separations were observed. The method was tested by separating green fluorescent protein (GFP) in hot embossed cyclic olefin polymer microchips with integrated fiber grooves for LIF detection. The sample adsorption was indirectly quantified by measuring the height, width and asymmetry of the separation peaks for various concentrations of nanoparticles in the sample and background electrolyte. Without nanoparticles, electropherograms displayed typical signs of extensive adsorption to the channel walls, with low, broad tailing peaks. Higher, narrower more symmetric peaks were generated when 0.5-10% nanoparticles were added, showing a dramatic reduction of sample adsorption. The current through the separation channel decreased with nanoparticle concentration, reducing to half its value when the nanoparticle concentration was increased from 0.5 to 4%. Addition of nanoparticles enabled separations that were otherwise hindered by extensive adsorption, e.g. separation of GFP mutants differing by only one amino acid. It was also observed that increasing the nanoparticle concentration increased the number of impurities that could be resolved in a GFP sample. This indicates that the adsorption is further reduced, and/or that the nanoparticles provide an interacting pseudostationary phase for electro-chromatography.
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| 4. |
- Petersson, Klara, et al.
(författare)
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Integrated acoustic sample preparation for rapid sepsis diagnostics
- 2014
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Ingår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014. - 9781634396974 - 9780979806476 ; , s. 294-296
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Konferensbidrag (refereegranskat)abstract
- We present a novel, integrated microfluidic system based on acoustophoretic cell-handling that detects bacteria in whole blood in less than 2 hours, substantially faster than current standard methods for detection of sepsis-causing bacteria. Bacteria are acoustically separated from 1 ml blood, enriched by acoustic trapping and finally detected using a dry-reagent PCR-chip.
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