| 1. |
- Aleklett, Kristin, et al.
(författare)
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Build your own soil : exploring microfluidics to create microbial habitat structures
- 2018
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Ingår i: ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 12:2, s. 312-319
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Forskningsöversikt (refereegranskat)abstract
- Soil is likely the most complex ecosystem on earth. Despite the global importance and extraordinary diversity of soils, they have been notoriously challenging to study. We show how pioneering microfluidic techniques provide new ways of studying soil microbial ecology by allowing simulation and manipulation of chemical conditions and physical structures at the microscale in soil model habitats.The ISME Journal advance online publication, 14 November 2017; doi:10.1038/ismej.2017.184.
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| 2. |
- Aleklett, Kristin, et al.
(författare)
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Fungal foraging behaviour and hyphal space exploration in micro-structured Soil Chips
- 2021
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Ingår i: The Isme Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370.
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Tidskriftsartikel (refereegranskat)abstract
- How do fungi navigate through the complex microscopic maze-like structures found in the soil? Fungal behaviour, especially at the hyphal scale, is largely unknown and challenging to study in natural habitats such as the opaque soil matrix. We monitored hyphal growth behaviour and strategies of seven Basidiomycete litter decomposing species in a micro-fabricated "Soil Chip" system that simulates principal aspects of the soil pore space and its micro-spatial heterogeneity. The hyphae were faced with micrometre constrictions, sharp turns and protruding obstacles, and the species examined were found to have profoundly different responses in terms of foraging range and persistence, spatial exploration and ability to pass obstacles. Hyphal behaviour was not predictable solely based on ecological assumptions, and our results obtained a level of trait information at the hyphal scale that cannot be fully explained using classical concepts of space exploration and exploitation such as the phalanx/guerrilla strategies. Instead, we propose a multivariate trait analysis, acknowledging the complex trade-offs and microscale strategies that fungal mycelia exhibit. Our results provide novel insights about hyphal behaviour, as well as an additional understanding of fungal habitat colonisation, their foraging strategies and niche partitioning in the soil environment.
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| 3. |
- Alsved, Julia, et al.
(författare)
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Label-free separation of peripheral blood mononuclear cells from whole blood by gradient acoustic focusing
- 2024
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Ingår i: Scientific Reports. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Efficient techniques for separating target cells from undiluted blood are necessary for various diagnostic and research applications. This paper presents acoustic focusing in dense media containing iodixanol to purify peripheral blood mononuclear cells (PBMCs) from whole blood in a label-free and flow-through format. If the blood is laminated or mixed with iodixanol solutions while passing through the resonant microchannel, all the components (fluids and cells) rearrange according to their acoustic impedances. Red blood cells (RBCs) have higher effective acoustic impedance than PBMCs. Therefore, they relocate to the pressure node despite the dense medium, while PBMCs stay near the channel walls due to their negative contrast factor relative to their surrounding medium. By modifying the medium and thus tuning the contrast factor of the cells, we enriched PBMCs relative to RBCs by a factor of 3600 to 11,000 and with a separation efficiency of 85%. That level of RBC depletion is higher than most other microfluidic methods and similar to that of density gradient centrifugation. The current acoustophoretic chip runs up to 20 µl/min undiluted whole blood and can be integrated with downstream analysis.
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| 4. |
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| 5. |
- Andersson, Klara, et al.
(författare)
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ANTISYMMETRIC ACTUATION INCREASES ACOUSTOPHORESIS PERFORMANCE
- 2021
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Ingår i: MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9781733419031 ; , s. 901-902
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Konferensbidrag (refereegranskat)abstract
- Antisymmetric, symmetric and standard actuation of acoustofluidic devices were compared in terms of focusability. By imaging the end part of an acoustophoresis separation channel while flowing fluorescent beads through it, we show that beads get more tightly focused by antisymmetric actuation than symmetric and standard actuation at a given electrical input power. This means that antisymmetric actuation is more suitable for single node acoustic focusing as lower input power can be used to reach the same level of performance, or higher throughput can be reached for the same power.
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| 6. |
- Arellano-Caicedo, Carlos, et al.
(författare)
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Habitat complexity affects microbial growth in fractal maze
- 2023
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Ingår i: Current biology : CB. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 33:8, s. 4-1458
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Tidskriftsartikel (refereegranskat)abstract
- The great variety of earth's microorganisms and their functions are attributed to the heterogeneity of their habitats, but our understanding of the impact of this heterogeneity on microbes is limited at the microscale. In this study, we tested how a gradient of spatial habitat complexity in the form of fractal mazes influenced the growth, substrate degradation, and interactions of the bacterial strain Pseudomonas putida and the fungal strain Coprinopsis cinerea. These strains responded in opposite ways: complex habitats strongly reduced fungal growth but, in contrast, increased the abundance of bacteria. Fungal hyphae did not reach far into the mazes and forced bacteria to grow in deeper regions. Bacterial substrate degradation strongly increased with habitat complexity, even more than bacterial biomass, up to an optimal depth, while the most remote parts of the mazes showed both decreased biomass and substrate degradation. These results suggest an increase in enzymatic activity in confined spaces, where areas may experience enhanced microbial activity and resource use efficiency. Very remote spaces showing a slower turnover of substrates illustrate a mechanism which may contribute to the long-term storage of organic matter in soils. We demonstrate here that the sole effect of spatial microstructures affects microbial growth and substrate degradation, leading to differences in local microscale spatial availability. These differences might add up to considerable changes in nutrient cycling at the macroscale, such as contributing to soil organic carbon storage.
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| 7. |
- Arellano-Caicedo, Carlos, et al.
(författare)
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Habitat geometry in artificial microstructure affects bacterial and fungal growth, interactions, and substrate degradation
- 2021
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Microhabitat conditions determine the magnitude and speed of microbial processes but have been challenging to investigate. In this study we used microfluidic devices to determine the effect of the spatial distortion of a pore space on fungal and bacterial growth, interactions, and substrate degradation. The devices contained channels differing in bending angles and order. Sharper angles reduced fungal and bacterial biomass, especially when angles were repeated in the same direction. Substrate degradation was only decreased by sharper angles when fungi and bacteria were grown together. Investigation at the cellular scale suggests that this was caused by fungal habitat modification, since hyphae branched in sharp and repeated turns, blocking the dispersal of bacteria and the substrate. Our results demonstrate how the geometry of microstructures can influence microbial activity. This can be transferable to soil pore spaces, where spatial occlusion and microbial feedback on microstructures is thought to explain organic matter stabilization.
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| 8. |
- Arellano-Caicedo, Carlos, et al.
(författare)
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Quantification of growth and nutrient consumption of bacterial and fungal cultures in microfluidic microhabitat models
- 2024
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Ingår i: STAR Protocols. - 2666-1667. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding microbes in nature requires consideration of their microenvironment. Here, we present a protocol for quantifying biomass and nutrient degradation of bacterial and fungal cultures (Pseudomonas putida and Coprinopsis cinerea, respectively) in microfluidics. We describe steps for mask design and fabrication, master printing, polydimethylsiloxane chip fabrication, and chip inoculation and imaging using fluorescence microscopy. We include procedures for image analysis, plotting, and statistics. For complete details on the use and execution of this protocol, please refer to Arellano-Caicedo et al. (2023).1
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| 9. |
- 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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| 10. |
- Hammer, Edith C., et al.
(författare)
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Hyphal exploration strategies and habitat modification of an arbuscular mycorrhizal fungus in microengineered soil chips
- 2024
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Ingår i: Fungal Ecology. - 1754-5048. ; 67
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Tidskriftsartikel (refereegranskat)abstract
- Arbuscular mycorrhizal fungi (AMF) are considered ecosystem engineers, but the interactions of their mycelium with their immediate surroundings are largely unknown. In this study, we used microfluidic chips, simulating artificial soil structures, to study foraging strategies and habitat modification of Rhizophagus irregularis symbiotically associated to carrot roots. AMF hyphae foraged over long distances in nutrient-void spaces, preferred straight over tortuous passages, anastomosed and showed strong inducement of branching when encountering obstacles. We measured bi-directional transport of cellular content inside active hyphae and documented strategic allocation of biomass within the mycelium via cytoplasm retraction from inefficient paths. R. irregularis modified pore-spaces in the chips by clogging pores with irregularly shaped spores. We suggest that studying AMF hyphal behaviour in spatial settings can explain phenomena reported at bulk scale such as AMF modification of water retention in soils. The use of microfluidic soil chips in AMF research opens up novel opportunities to study their ecophysiology and interactions with both biotic and abiotic factors.
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