| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Saharil, Farizah, 1976-, et al.
(författare)
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SUPERIOR DRY BONDING OF OFF-STOICHIOMETRY THIOL-ENEEPOXY (OSTE(+)) POLYMERS FOR HETEROGENEOUS MATERIALLABS-ON-CHIP
- 2012
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Ingår i: Proceedings Micro Total Analysis Systems (muTAS) 2012. - 9780979806452 ; , s. 1831-1833
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Konferensbidrag (refereegranskat)abstract
- We demonstrate biocompatible bonding to a multitude of LoC substrates using OSTE(+), a novel polymer formulation with a unique dual cure system developed specifically for microfluidic applications. OSTE(+) allows for soft lithography microstructuring, strong biocompatible dry bonding to almost any substrate during LoCmanufacturing, while simultaneously mimicking the mechanical properties found in thermoplastic polymers, hence allowing for true prototyping of commercial LoCs. In this work, we describe the simple micropatterning process, curing mechanisms and show leak-free dry bonding to nine different substrate materials. Uniquely, strong bonding is achieved to COC, the thermoplastic of choice for microfluidics, which opens up the possibility of hybrid thermoplastic/OSTE(+) LoCs. In this work, we demonstrate bonding to nine different untreated substrates at 37°C and room temperature to demonstrate good bonding properties even at lower temperature. We also show the high resilience of the epoxy bond by immersing an aluminum substrate with a bonded OSTE(+) layer into boiling water while simultaneously subjecting the assembly to pressurized air.
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| 6. |
- Salm, E., et al.
(författare)
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Integrated 'lab-on-a-transistor' : With droplets-in-air for parallel nanoliter reactions
- 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. 1945-1947
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Konferensbidrag (refereegranskat)abstract
- We aim to take 'lab-on-chip' technology further by introducing the concept of a 'lab-on-transistor'. In this methodology, laboratory operations, such as heating, cell lysis, and detection, are performed on a single transistor instead of on an entire microchip. To demonstrate this concept, we developed a heating technique that allows transistors to act as electrically addressable, individual heating units. We have coupled the transistor heaters with placement of sub-nanoliter droplets to create individual heated reaction volumes. Under this configuration transistors become highly localized heater/sensors capable of high-speed thermocycling (>25°C/s) of <1nL reactions with potential for electrical detection of biological analytes.
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| 7. |
- Sjöström, Staffan L., et al.
(författare)
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Multiplex analysis of enzyme kinetics and inhibition by droplet microfluidics using picoinjectors
- 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. 172-174
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Konferensbidrag (refereegranskat)abstract
- We present a novel microdroplet-based device for extensive characterization of the reaction kinetics of enzymeinhibitor systems in a single experiment, for the first time utilizing droplet picoinjectors for bioanalysis. This device enables the scanning of multiple inhibitors, inhibitor concentrations and substrate conditions in a single, highly time resolved experiment yielding the Michaelis constant (Km), the turnover number (Kcat) the mode of inhibition and the inhibitor enzyme binding constants (Ki, Ki). Using this device we determine Km and Kcat for β-galactosidase and the fluorogenic substrate Resorufin β-D-galactopyranoside (RBG) to 252 μM and 477 s-1, respectively. Furthermore, we examine the inhibitory effects of Phenylethyl β-D-thiogalactopyranoside (PETG) on this system.
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| 8. |
- Weibull, Emilie, et al.
(författare)
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Development of a microfluidic concentration gradient generator on a microwell slide for high-throughput cell analysis
- 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. 1573-1575
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Konferensbidrag (refereegranskat)abstract
- The present study reports a newly developed, microfluidic concentration gradient generator that adds substantial utility to the high-throughput nature of the microwell slide that we have previously established [1, 2]. Using microfluidic dynamics, we have designed microchannels to deliver a reagent and its dilutant with precisely controlled flow volumes, generating 8 discrete steps of reagent concentration in designated microwells. As proof of concept FITC-labeled dextran and dextran-free water was used to visualize the concentration gradient. The next step will be to perform cancer drug concentration gradient experiments on an animal cell line.
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