| 1. |
- Ardabili, Sahar, et al.
(författare)
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Dean flow-coupled inertial focusing for ultra-high-throughput particle filtration
- 2010
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Ingår i: 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010. - 9781618390622 ; , s. 1586-1588
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Konferensbidrag (refereegranskat)abstract
- Particle manipulation represents an important and fundamental step prior to counting, sorting and detecting bio-particles. In this study, we report dean-coupled inertial focusing of particles in flows through a single curve microchannel at extremely high channel Reynold numbers (∼325). We found the lateral particle focusing position, xf to be fixed and largely independent of radius of curvature and whether particles are pre-focused (at equilibrium) entering the curvature or randomly distributed. Finally, using a single inlet, u-shaped, microchannel we demonstrate filtration of 10μm particles from 2 μm particles at throughputs several orders of magnitude higher than previously shown.
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| 2. |
- Hansson, Jonas, et al.
(författare)
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Inertial microfluidics in parallel channels for high-throughput applications
- 2012
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 12:22, s. 4644-4650
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Tidskriftsartikel (refereegranskat)abstract
- Passive particle focusing based on inertial microfluidics was recently introduced as a high-throughput alternative to active focusing methods that require an external force-field to manipulate particles. In this study, we introduce inertial microfluidics in flows through straight, multiple parallel channels. The scalable, single inlet and two outlet, parallel channel system is enabled by a novel, high-density 3D PDMS microchannel manufacturing technology, mediated via a targeted inhibition of PDMS polymerization. Using single channels, we first demonstrate how randomly distributed particles can be focused into the centre position of the channel in flows through low aspect ratio channels and can be effectively fractionated. As a proof of principle, continuous focusing and filtration of 10 μm particles from a suspension mixture using 4- and 16-parallel-channel devices with a single inlet and two outlets are demonstrated. A filtration efficiency of 95-97% was achieved at throughputs several orders of magnitude higher than previously shown for flows through straight channels. The scalable and low-footprint focusing device requiring neither external force fields nor mechanical parts to operate is readily applicable for high-throughput focusing and filtration applications as a stand-alone device or integrated with lab-on-a-chip systems.
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| 3. |
- Hansson, Jonas, 1983-
(författare)
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Microfluidic blood sample preparation for rapid sepsis diagnostics
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sepsis, commonly referred to as blood poisoning, is a serious medical condition characterized by a whole-body inflammatory state caused by microbial infection. Rapid treatment is crucial, however, traditional culture-based diagnostics usually takes 2-5 days. The overall aim of the thesis is to develop microfluidic based sample preparation strategies, capable of isolating bacteria from whole blood for rapid sepsis diagnostics. Although emerging technologies, such as microfluidics and “lab-on-a-chip” (LOC) devices have the potential to spur the development of protocols and affordable instruments, most often sample preparation is performed manually with procedures that involve handling steps prone to introducing artifacts, require skilled technicians and well-equipped, expensive laboratories. Here, we propose the development of methods for fast and efficient sample preparation that can isolate bacteria from whole blood by using microfluidic techniques with potential to be incorporated in LOC systems. We have developed two means for high throughput bacteria isolation: size based sorting and selective lysis of blood cells. To process the large blood samples needed in sepsis diagnostics, we introduce novel manufacturing techniques that enable scalable parallelization for increased throughput in miniaturized devices. The novel manufacturing technique uses a flexible transfer carrier sheet, water-dissolvable release material, poly(vinyl alcohol), and a controlled polymerization inhibitor to enable highly complex polydimethylsiloxane (PDMS) structures containing thin membranes and 3D fluidic networks. The size based sorting utilizes inertial microfluidics, a novel particles focusing method that operates at extremely high flow rates. Inertial focusing in flow through a single inlet and two outlet, scalable parallel channel devices, was demonstrated with filtration efficiency of >95% and a flowrate of 3.2 mL/min. Finally, we have developed a novel microfluidic based sample preparation strategy to continuously isolate bacteria from whole blood for downstream analysis. The method takes advantage of the fact that bacteria cells have a rigid cell wall protecting the cell, while blood cells are much more susceptible to chemical lysis. Whole blood is continuously mixed with saponin for primary lysis, followed by osmotic shock in water. We obtained complete lysis of all blood cells, while more than 80% of the bacteria were readily recovered for downstream processing. Altogether, we have provided new bacteria isolation methods, and improved the manufacturing techniques and microfluidic components that, combined offer the potential for affordable and effective sample preparation for subsequent pathogen identification, all in an automated LOC format.
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| 4. |
- Xu, Hao, et al.
(författare)
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Modulated fluorescence of colloidal quantum dots embedded in a porous alumina membrane
- 2013
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 177:45, s. 14151-14156
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Tidskriftsartikel (refereegranskat)abstract
- The fluorescence spectrum of CdSe core-CdS/ZnS shell colloidal quantum dots (QDs) embedded in porous alumina membrane was studied. Small peaks, superimposed on the principal QD fluorescence spectrum, were observed. Finite-difference time-domain simulation indicates that the QD point radiation emitting from within the membrane is strongly modulated by the photonic band structure introduced by the membrane pores, leading to the observed fine spectral features. Moreover, the principal QD fluorescence peak red-shifted when the optical excitation power was increased, which is attributed to QD material heating due to emitted phonons when the photoexcited electron and hole relax nonradiatively from high-energy states to the ground exciton state before fluorescence.
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| 5. |
- Zelenin, S., et al.
(författare)
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Bacteria isolation from whole blood for sepsis diagnostics
- 2011
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Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; , s. 518-520
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Konferensbidrag (refereegranskat)abstract
- Rapid and reliable detection of bloodstream infections would gain a lot from improved and straightforward isolation of highly purified bacteria from whole blood. Here, we report a microfluidics-based sample preparation strategy to continuously isolate microorganisms from whole blood for downstream analysis. The continuous-flow method takes advantage of the fact that bacteria cells have rigid cell wall enables selective and complete blood cell lysis while ~ 100% of bacteria are readily recovered. The method as a sample preparation unit offers opportunities to develop molecular based POC for sepsis diagnostics.
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| 6. |
- Zelenin, Sergey, et al.
(författare)
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Microfluidic-based isolation of bacteria from whole blood for sepsis diagnostics
- 2015
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Ingår i: Biotechnology letters. - : Springer Science and Business Media LLC. - 0141-5492 .- 1573-6776. ; 37:4, s. 825-830
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Tidskriftsartikel (refereegranskat)abstract
- Blood-stream infections (BSI) remain a major health challenge, with an increasing incidence worldwide and a high mortality rate. Early treatment with appropriate antibiotics can reduce BSI-related morbidity and mortality, but success requires rapid identification of the infecting organisms. The rapid, culture-independent diagnosis of BSI could be significantly facilitated by straightforward isolation of highly purified bacteria from whole blood. We present a microfluidic-based, sample-preparation system that rapidly and selectively lyses all blood cells while it extracts intact bacteria for downstream analysis. Whole blood is exposed to a mild detergent, which lyses most blood cells, and then to osmotic shock using deionized water, which eliminates the remaining white blood cells. The recovered bacteria are 100 % viable, which opens up possibilities for performing drug susceptibility tests and for nucleic-acid-based molecular identification.
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| 7. |
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