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- Cruz, Javier, 1990-, et al.
(författare)
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Stable 3D Inertial Focusing by High Aspect Ratio Curved Microfluidics
- 2021
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Ingår i: Journal of Micromechanics and Microengineering. - : Institute of Physics Publishing (IOPP). - 0960-1317 .- 1361-6439. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- Fine manipulation of particles is essential for the analysis of complex samples such as blood or environmental water, where rare particles of interest may be masked by millions of others. Inertial focusing is amongst the most promising techniques for this task, enabling label-free manipulation of particles with sub-micron resolution at very high flow rates. However, the phenomenon still remains difficult to predict due to the focus position shifting in tortuous ways as function of the channel geometry, flow rate and particle size. Here, we present a new line of microfluidics that exploit inertial focusing in High Aspect Ratio Curved (HARC) microchannels and overcome this limitation. Consisting of a single curved channel, HARC systems provide a highly predictable, single focus position near the centre of the inner wall, largely independent of the flow rate and particle size.An explanation of the mechanism of migration and focus of particles, together with its governing equations, is provided based on simulations in COMSOL Multiphysics and experimental results. HARC microchannels built in silicon-glass were used for experimental validation, achieving a high quality, single focus position for a range of microparticles with sizes of 0.7 - 1 µm and bacterial cells (Escherichia coli). The recovery of 1 µm particles was 99.84% with a factor four in concentration.With a stable focus position, we envision that HARC systems will bring the technology closer to implementation in laboratories for analysis of complex fluids with biological particles like cells and organelles.
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| 5. |
- Cruz, Javier, 1990-, et al.
(författare)
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High-resolution particle separation by inertial focusing in high aspect ratio curved microfluidics
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- The ability to focus, separate and concentrate specific targets in a fluid is essential for the analysis of complex samples such as biological fluids, where a myriad of different particles may be present. Inertial focusing is a very promising technology for such tasks, and specially a recently presented variant, inertial focusing in High Aspect Ratio Curved systems (HARC systems), where the systems are easily engineered and focus the targets together in a stable position over a wide range of particle sizes and flow rates. However, although convenient for laser interrogation and concentration, by focusing all particles together, HARC systems lose an essential feature of inertial focusing: the possibility of particle separation by size. Within this work, we report that HARC systems not only do have the capacity to separate particles but can do so with extremely high resolution, which we demonstrate for particles with a size difference down to 80 nm. In addition to the concept for particle separation, a model considering the main flow, the secondary flow and a simplified expression for the lift force in HARC microchannels was developed and proven accurate for the prediction of the performance of the systems. The concept was also demonstrated experimentally with three different sub-micron particles (0.79, 0.92 and 1.0 mu m in diameter) in silicon-glass microchannels, where the resolution in the separation could be modulated by the radius of the channel. With the capacity to focus sub-micron particles and to separate them with high resolution, we believe that inertial focusing in HARC systems is a technology with the potential to facilitate the analysis of complex fluid samples containing bioparticles like bacteria, viruses or eukaryotic organelles.
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| 6. |
- Cruz, Javier, 1990-
(författare)
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Microfluidics for High-Pressure Inertial Focusing : Focusing, Separation and Concentration of Micro and Sub-micron Particles
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The birth of microsystems set the ground for technologies never imagined before, for it is not only the small size what characterizes the miniaturized systems, but unique phenomena arise in the micro scale. This thesis relates to one such unique phenomenon, inertial focusing, a phenomenon that occurs in microfluidic systems if very special conditions are met and that allows for fine manipulation of particles in fluid samples. This ability is key in a bigger picture: the analysis of complex fluids, where rare particles of interest may be present in very few numbers amongst a myriad of others, making the task difficult – if not impossible. A system exploiting inertial focusing allows, for instance, to focus, separate, isolate and concentrate such rare particles of interest, and even to transfer them to another fluid, thereby enabling/facilitating their detection and analysis. Examples of rare particles of interest in complex fluids are circulating tumor cells in blood, that give away the presence of cancer, extracellular vesicles also in blood, that contain biomarkers with physiological and pathological information about the patient, or bacteria in natural water, where the species present and their numbers are to be monitored for safety reasons and/or biological studies. This thesis covers the state of art physical principles behind the phenomenon and extends the understanding both in theory and applications. Specifically, the technology is extended to allow for manipulation of sub-micron particles, a range of interest as it comprises bacteria, viruses and organelles of eukaryotic cells. This was possible by an analysis of the balance of forces in play and by the integration of inertial focusing in high-pressure systems (up to 200 bar). In a second block, a very special line of inertial focusing is introduced and developed; inertial focusing in High Aspect Ratio Curved (HARC) microfluidics. These systems, engineered to rearrange the force field responsible for the particle manipulation, not only achieve excellent performances for focusing and concentration of particles, but also extreme resolution in their separation (mathematically unlimited; demonstrated experimentally for differences in size down to 80 nm). Perhaps more important than the performance, the systems are stable, intuitive and simpler to design, attributes that we hope will make the technology and its outstanding benefits more accessible to the community. With its remarkable performance, it would not come as a surprise if, in the near future, inertial focusing makes a strong impact on how analyses are performed nowadays and opens up for possibilities beyond the current state of the art.
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| 8. |
- Cruz, Javier, 1990-, et al.
(författare)
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The upper limit and lift force within inertial focusing in high aspect ratio curved microfluidics
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Microfluidics exploiting the phenomenon of inertial focusing have attracted much attention in the last decade as they provide the means to facilitate the detection and analysis of rare particles of interest in complex fluids such as blood and natural water. Although many interesting applications have been demonstrated, the systems remain difficult to engineer. A recently presented line of the technology, inertial focusing in High Aspect Ratio Curved microfluidics, has the potential to change this and make the benefits of inertial focusing more accessible to the community. In this paper, with experimental evidence and fluid simulations, we provide the two necessary equations to design the systems and successfully focus the targets in a single, stable, and high-quality position. The experiments also revealed an interesting scaling law of the lift force, which we believe provides a valuable insight into the phenomenon of inertial focusing.
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- Hellström, Daniel, et al.
(författare)
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Systemförändring för omställning till hållbar e-handel : Kraftsamling som accelererar innovation
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- E-handeln ökar snabbare än någonsin vilket medför en mängd hållbarhetsutmaningar för hela samhället. För att nå de globala målen råder inget tvivel om att vi behöver transformera e-handel till ett hållbart system. Likaså vet vi att kunskap och innovation är avgörande för att ge sig på denna komplexa samhällsutmaning. Men vilka områden behövs förändras för att åstadkomma stor effekt på hela systemet och på så sätt bidrar till den omställning som framtiden kräver? Vilka knäckfrågor måste adresseras? Detta undersöktes i en workshopserie, baserat på Design Thinking metodik, för att få en tydlig behovsbild över vilka frågor och centrala områden som kräver en genomgripande förändring.Med hjälp av aktörer från olika privata och offentliga sektorer, branscher och discipliner identifierades åtta sammanhängande problemområden. Dessa områden är starkt sammanhängande och kretsar kring ”den hållbara leveransen”. Genom att skapa förändringar på något av dessa områden skapas stor effekt på hela systemet vilket kan bidrar till den omställning som eftersträvas. De är följande:1. Konsumtion och livsstil2. Leveransplatser3. Dynamisk och flexibel leverans4. Retur5. Förpackningssystem6. Försörjning och logistik7. Samordnad distribution8. StadsplaneringFör att effektivt åstadkomma genomgripande systemförändring finns det ett tydligt behov att kraftsamla kring de identifierade områdena. De viktigaste orsakerna till behovet av en central kraftsamling är:• Det saknas ett helhetsgrepp och sammanhållen nod för strategisk koordinering av initiativ• Det råder stor kunskapsbrist hos likväl företag och offentlig sektor som hos konsumenterna – det behövs en drivande part för att fylla kunskapsgapet• Marknaden kan inte lösa problematiken på egen hand utan behöver stöd och guidning för hur vi tillsammans tar oss hållbart framåt• Få igång och intensifiera samordning och strategisk koordinering mellan det offentliga och privataFörlag till kraftsamling är en integrerad samverkansarena och kompetenscenter för hållbar e-handel där CLOSER och ReLog ingår ett strategiskt samarbete för att binda samman kompetenser och gemensamt driva forskning- och innovationsprojekt. Förslaget innebär en ny och helt unik samverkansmiljö där vi integrerar två nationellt starka kunskapsnoder, skapar en sammanhållande nod med vetenskapligt- och behovsbaserad projektverkstad som tar ett helhetsgrepp på e-handelns möjligheter och utmaningar. CLOSER och ReLog har gemensamt ett upparbetat strukturkapital och ett nationellt renommé för att driva komplexa samverkansprojekt i gränssnitt mellan offentliga och privata aktörer. Sammanvävningen innebär en konsolidering av två starka nätverk inom olika sektorer, branscher, och mellan offentliga och privata aktörer – en förutsättning för att få förändring på plats eftersom ingen har förmågan att åstadkomma systemförändring ensamt, men tillsammans har de unika möjligheter.
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| 10. |
- Hellström, Daniel, et al.
(författare)
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Så ställer vi om till hållbar e-handel
- 2021
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Ingår i: Supply Chain Effect. - 2000-8457. ; 2021:2, s. 38-41
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- E-commerce is a complex societal challenge with an enormous potential to contribute to sustainable development. In order to capture this potential and transform e-commerce into a sustainable system requires radical change. But which areas are in need of change in order to achieve a grand effect and what key issues must addressed?
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