| 1. |
- Augustsson, P., et al.
(författare)
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Acoustop horesis pre-alignment of cells enables labelfree enrichment of prostate cancer cells in blood
- 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. 1696-1698
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Konferensbidrag (refereegranskat)abstract
- We have developed a microfluidic chip for isolation of circulating tumor cells (CTCs) in blood based on microchannel acoustophoresis. Ultrasound radiation forces are used to separate cancer cells from blood cells in a continuous flow format. Separation was dramatically improved after incorporation of a 2-dimensional acoustic pre-alignment of the cells before entering the acoustophoresis separation channel. Temperature regulation of the microfluidic chip (±0.5?C) enabled stable and reproducible separation. The chip constitutes a further development and refinement of methods previously presented by our group at μTAS [1-3].
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| 2. |
- Beech, Jason P., et al.
(författare)
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Sample preparation for single-cell whole chromosome analysis
- 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. 998-999
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Konferensbidrag (refereegranskat)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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| 3. |
- Christakou, Athanasia E., et al.
(författare)
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Characterization of natural killer cells' cytotoxic heterogeneity using an array of sono-cages
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - : Chemical and Biological Microsystems Society. - 9780979806452 ; , s. 1555-1557
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Konferensbidrag (refereegranskat)abstract
- Using a multi-well device as an array of sono-cages for single cell analysis, we quantify for the first time the heterogeneity of natural killer (NK) cells' cytotoxic response against cancer cells. We report a fraction of inactive NK cells within the tested population (36%), as well as the existence of few 'serial killers' that eliminate up to six targets during 4 hours. We also characterize the multi-well acoustic device in terms of trapping efficiency at different actuation voltages, using adherent and non-adherent cell lines. We show that the acoustic forces applied on the cells can be compared to forces of biological processes (i.e. cell adherence).
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| 4. |
- 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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| 5. |
- Fritzsche, Joachim, 1977, et al.
(författare)
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A lipid-based passivation scheme for nanofluidics
- 2012
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Ingår i: 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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Konferensbidrag (refereegranskat)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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| 6. |
- Ghasemi, Masoomeh, et al.
(författare)
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Separation of deformable hydrogel microparticles in deterministic lateral displacement devices
- 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. 1672-1674
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Konferensbidrag (refereegranskat)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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| 7. |
- Holm, Stefan H., et al.
(författare)
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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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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 530-532
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Konferensbidrag (refereegranskat)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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| 8. |
- Ohlander, A., et al.
(författare)
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DNA melting curve analysis on semi-transparent thin film microheater on flexible lab-on-foil substrate
- 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. 797-799
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Konferensbidrag (refereegranskat)abstract
- This paper presents genotyping on a novel microheater concept using semi-transparent copper microheaters manufactured by roll-to-roll and lift-off on polyethylene napthalate (PEN) foil. Using a mesh structure, heater surfaces have been realized in one single metallization step with a manufacturing robustness higher than conventional meander structures. The thermal distribution of the meshes, evaluated using thermochromic-liquid-crystals (TLC), produced more homogenous heating characteristics compared to meanders. Parylene coated heaters were functionalized using copolymer poly(DMA-NAS-MAPS) to enable covalent DNA immobilization and successful melting curve analysis was performed differentiating between match and mismatch oligonucleotides.
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| 9. |
- Ohlin, Mathias, et al.
(författare)
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Analysis of trapping and streaming in an ultrasoundactuated multi-well microplate for single-cell studies
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - : Chemical and Biological Microsystems Society. - 9780979806452 ; , s. 497-499
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Konferensbidrag (refereegranskat)abstract
- The dynamics of the acoustic streaming and the acoustic positioning performance in an ultrasound-actuated multiwell microplate are investigated by two different ultrasonic frequency actuation schemes: Frequency-modulation and single- frequency actuation. Our results show a significant decrease in size of the field of view when using frequencymodulation compared to single-frequency actuation, which can be used for improving the scanning time for 3D highresolution confocal microscopy by almost one order of magnitude. Furthermore, in the ultrasound-actuated multi-well microplate the high-voltage acoustic streaming show a complex time and temperature dependence and could gain stability by the use of temperature control.
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| 10. |
- Ramachandraiah, Harisha, et al.
(författare)
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Centrifugal microfluidic system for rapid, low-cost HIV diagnosis : CD4+ T-cell counting using an integrated DVD platform
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - : Chemical and Biological Microsystems Society. - 9780979806452 ; , s. 1942-1944
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Konferensbidrag (refereegranskat)abstract
- HIV is a pandemic that currently threatens over 33 million lives worldwide and HIV/AIDS remains one of the major causes of death globally. The continued monitoring of the CD4+ T-lymphocytes count in HIV patients is necessary for proper treatment, although this testing is too expensive and complex for limited resource settings. We report on a novel integrated centrifugal (CD) microfluidic system for rapid and low-cost HIV diagnosis through automated counting of CD4+ T-cells for point-of-care applications. We demonstrate the integrated T-cell immunocapture and detection mechanism using a novel system comprised of a modified commercial DVD drive and polymer disc.
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