| 1. |
- Ciftci, Sibel, 1987-, et al.
(författare)
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The sweet detection of rolling circle amplification : Glucose-based electrochemical detection of virus nucleic acid
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Infectious diseases remain a constant threat on a global scale by recurring pandemics. Rapid and portable diagnostics hold the promise to tackle the spreading of diseases and decentralizing healthcare to point-of-care needs. Ebola, a hypervariable RNA virus causing fatalities of up to 90% for recent outbreaks in Africa, demands immediate attention for bedside diagnostics. Nucleic acid amplification technology (NAAT) has proven to be a powerful tool for the control of outbreak with high sensitivity and specificity. However, NAAT is mostly based on amplification methods that require specialized instrumentation and trained personnel, such as PCR with sophisticated detectors. Here, we present an isothermal padlock probe-based assay for the detection of pathogens coupled with a glucose oxidase (GOx)-based electrochemical approach as the read-out. The assay design is based on rolling circle amplification (RCA) upon magnetic beads, connecting the RCA products (RCPs) via streptavidin-biotin bridges to GOx needed for the electrochemical measurement with externally provided glucose. The RCPs forming on the surface of beads are imaged using scanning electron microscopy, and the presence of the GOx to the RCP complex is confirmed using atomic force microscopy. Parameters such as the choice of buffers, concentrations of glucose and GOx and measurement time were optimized, as well as the mode of addition of glucose was tested. 125 μg/mL of GOx with 5 mM glucose using PBS as washing buffer, monitored for 15 min were chosen as the optimized conditions. The effect of temperature was tested and found to be critical at 37 °C for enhanced performance of the sensor. Finally, we evaluate the analytical performance of our sensor system by using cell culture isolate and clinical samples of Ebola virus. The study provides a proof-of-concept of simple and portable molecular diagnostics for emerging pathogens, beneficial especially for resource-limited settings.
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| 2. |
- Ghorbani, Morteza, et al.
(författare)
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Unravelling the Acoustic and Thermal Responses of Perfluorocarbon Liquid Droplets Stabilized with Cellulose Nanofibers
- 2019
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Ingår i: Langmuir. - : American Chemical Society. - 0743-7463 .- 1520-5827. ; 35:40, s. 13090-13099
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Tidskriftsartikel (refereegranskat)abstract
- The attractive colloidal and physicochemical properties of cellulose nanofibers (CNFs) at interfaces have recently been exploited in the facile production of a number of environmentally benign materials, e.g. foams, emulsions, and capsules. Herein, these unique properties are exploited in a new type of CNF-stabilized perfluoropentane droplets produced via a straightforward and simple mixing protocol. Droplets with a comparatively narrow size distribution (ca. 1-5 μm in diameter) were fabricated, and their potential in the acoustic droplet vaporization process was evaluated. For this, the particle-stabilized droplets were assessed in three independent experimental examinations, namely temperature, acoustic, and ultrasonic standing wave tests. During the acoustic droplet vaporization (ADV) process, droplets were converted to gas-filled microbubbles, offering enhanced visualization by ultrasound. The acoustic pressure threshold of about 0.62 MPa was identified for the cellulose-stabilized droplets. A phase transition temperature of about 22 °C was observed, at which a significant fraction of larger droplets (above ca. 3 μm in diameter) were converted into bubbles, whereas a large part of the population of smaller droplets were stable up to higher temperatures (temperatures up to 45 °C tested). Moreover, under ultrasound standing wave conditions, droplets were relocated to antinodes demonstrating the behavior associated with the negative contrast particles. The combined results make the CNF-stabilized droplets interesting in cell-droplet interaction experiments and ultrasound imaging.
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| 3. |
- Kaiser, Thomas, et al.
(författare)
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When will smart antennas be ready for the market? : Part I
- 2005
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Ingår i: IEEE signal processing magazine (Print). - 1053-5888 .- 1558-0792. ; 22:2, s. 87-92
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This work aims to shed more light on the issue of why smart antennas haven't yet penetrated the market despite all the research efforts that have been put into the technology. The paper looks at this issue from various perspectives and subdivides the discussions into fixed or nomadic and high mobility applications because of the different types of markets, demands, and technological barriers.
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| 4. |
- Kaiser, Thomas, et al.
(författare)
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When will smart antennas be ready for the market? : Part II - results
- 2005
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Ingår i: IEEE signal processing magazine (Print). - 1053-5888 .- 1558-0792. ; 22:6, s. 174-176
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this two-part forum is to shed more light on the future of smartantennas (SA) through discussions among a balanced group of experts from academia and industry. In part I, which appeared in the March 2005 issue of IEEE Signal Processing Magazine, each of the experts stated his own opinion after exchanging some thoughts by e-mail. Then, a panel session took place at ICAS-SP'05 and a public poll followed. Now, in part II, the results are summarized by the experts. The central topic of the forum was the expectedmarket breakthrough of SA.
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| 5. |
- Nordenström, Malin, et al.
(författare)
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Superamphiphobic coatings based on liquid-core microcapsules with engineered capsule walls and functionality
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Microcapsules with specific functional properties, related to the capsule wall and core, are highly desired in a number of applications. In this study, hybrid cellulose microcapsules (1.2 ± 0.4 µm in diameter) were prepared by nanoengineering the outer walls of precursor capsules. Depending on the preparation route, capsules with different surface roughness (raspberry or broccoli-like), and thereby different wetting properties, could be obtained. The tunable surface roughness was achieved as a result of the chemical and structural properties of the outer wall of a precursor capsule, which combined with a new processing route allowed in-situ formation of silica nanoparticles (30-40 nm or 70 nm in diameter). By coating glass slides with "broccoli-like" microcapsules (30-40 nm silica nanoparticles), static contact angles above 150° and roll-off angles below 6° were obtained for both water and low surface-tension oil (hexadecane), rendering the substrate superamphiphobic. As a comparison, coatings from raspberry-like capsules were only strongly oleophobic and hydrophobic. The liquid-core of the capsules opens great opportunities to incorporate different functionalities and here hydrophobic superparamagnetic nanoparticles (SPIONs) were encapsulated. As a result, magnetic broccoli-like microcapsules formed an excellent superamphiphobic coating-layer on a curved geometry by simply applying an external magnetic field.
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| 7. |
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| 8. |
- Paulraj, Thomas, et al.
(författare)
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Bioinspired capsules based on nanocellulose, xyloglucan and pectin - The influence of capsule wall composition on permeability properties
- 2018
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 69, s. 196-205
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Tidskriftsartikel (refereegranskat)abstract
- Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility. The live cell staining revealed that the microcapsules' surface enhanced cell growth and also the non-toxic nature of the microcapsules. In water, the microcapsules were completely and partially permeable to fluorescent dextrans with an average molecular weight of 70 kDa (hydrodynamic diameter of ca. 12 nm) and 2000 kDa (ca. 54 nm), respectively. On the other hand, the permeability dropped quickly when the capsules were exposed to 250 mM NaCl solution, trapping a fraction of the 70 kDa dextrans in the capsule interior. The decrease in permeability was a direct consequence of the capsule-wall composition, i.e. the presence of xyloglucan and a low amount of charged molecules such as pectin. The low permeability of capsules in saline conditions (and in a model biological medium), combined with a capsule wall that is made from dietary fibers only, potentially enables their use in biological applications, such as colon targeted delivery in the gastro-intestinal tract.
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| 9. |
- Paulraj, Thomas, et al.
(författare)
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Bioinspired Layer-by-Layer Microcapsules Based on Cellulose Nanofibers with Switchable Permeability
- 2017
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 18:4, s. 1401-1410
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Tidskriftsartikel (refereegranskat)abstract
- Green, all-polysaccharide based microcapsules with mechanically robust capsule walls and fast, stimuli-triggered, and switchable permeability behavior show great promise in applications based on selective and timed permeability. Taking a cue from nature, the build-up and composition of plant primary cell walls inspired the capsule wall assembly, because the primary cell walls in plants exhibit high mechanical properties despite being in a highly hydrated state, primarily owing to cellulose microfibrils. The micro capsules (16 +/- 4 mu m in diameter) were fabricated using the layer-by-layer technique on sacrificial CaCO3 templates, using plant polysaccharides (pectin, cellulose nanofibers, and xyloglucan) only. In water, the capsule wall was permeable to labeled dextrans with a hydrodynamic diameter of similar to 6.6 nm. Upon exposure to NaC1, the porosity of the capsule wall quickly changed allowing larger molecules (similar to 12 nm) to permeate. However, the porosity could be restored to its original state by removal of NaCl, by which permeants became trapped inside the capsule's core. The high integrity of cell wall was due to the CNF and the ON/OFF alteration of the permeability properties, and subsequent loading/unloading of molecules, could be repeated several times with the same capsule demonstrating a robust microcontainer with controllable permeability properties.
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