| 1. |
- Andersson, Martin, et al.
(författare)
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A microscopy-compatible temperature regulation system for single-cell phenotype analysis - demonstrated by thermoresponse mapping of microalgae
- 2021
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 21:9, s. 1694-1705
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Tidskriftsartikel (refereegranskat)abstract
- This work describes a programmable heat-stage compatible with in situ microscopy for the accurate provision of spatiotemporally defined temperatures to different microfluidic devices. The heat-stage comprises an array of integrated thin-film Joule heaters and resistance temperature detectors (RTDs). External programming of the heat-stage is provided by a custom software program connected to temperature controllers and heater–sensor pairs. Biologically relevant (20–40 °C) temperature profiles can be supplied to cells within microfluidic devices as spatial gradients (0.5–1.5 °C mm−1) or in a time-varying approach via e.g. step-wise or sinusoidally varying profiles with negligible temperature over-shoot. Demonstration of the device is achieved by exposing two strains of the coral symbiont Symbiodinium to different temperature profiles while monitoring their single-cell photophysiology via chlorophyll fluorometry. This revealed that photophysiological responses to temperature depended on the exposure duration, exposure magnitude and strain background. Moreover, thermal dose analysis suggested that cell acclimatisation occurs under longer temperature (6 h) exposures but not under shorter temperature exposures (15 min). As the thermal sensitivity of Symbiodinium mediates the thermal tolerance in corals, our versatile technology now provides unique possibilities to research this interdependency at single cell resolution. Our results also show the potential of this heat-stage for further applications in fields such as biotechnology and ecotoxicology.
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| 2. |
- Asri, Mohd Afiq Mohd, et al.
(författare)
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Low-cost and rapid prototyping of integrated electrochemical microfluidic platforms using consumer-grade off-the-shelf tools and materials
- 2022
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Ingår i: Lab on a Chip. - : ROYAL SOC CHEMISTRY. - 1473-0197 .- 1473-0189. ; 22:9, s. 1779-1792
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Tidskriftsartikel (refereegranskat)abstract
- We present a low-cost, accessible, and rapid fabrication process for electrochemical microfluidic sensors. This work leverages the accessibility of consumer-grade electronic craft cutters as the primary tool for patterning of sensor electrodes and microfluidic circuits, while commodity materials such as gold leaf, silver ink pen, double-sided tape, plastic transparency films, and fabric adhesives are used as its base structural materials. The device consists of three layers, the silver reference electrode layer at the top, the PET fluidic circuits in the middle and the gold sensing electrodes at the bottom. Separation of the silver reference electrode from the gold sensing electrodes reduces the possibility of cross-contamination during surface modification. A novel approach in mesoscale patterning of gold leaf electrodes can produce generic designs with dimensions as small as 250 mu m. Silver electrodes with dimensions as small as 385 mu m were drawn using a plotter and a silver ink pen, and fluid microchannels as small as 300 mu m were fabricated using a sandwich of iron-on adhesives and PET. Device layers are then fused together using an office laminator. The integrated microfluidic electrochemical platform has electrode kinetics/performance of Delta E-p = 91.3 mV, I-pa/I-pc = 0.905, characterized by cyclic voltammetry using a standard ferrocyanide redox probe, and this was compared against a commercial screen-printed gold electrode (Delta E-p = 68.9 mV, I-pa/I-pc = 0.984). To validate the performance of the integrated microfluidic electrochemical platform, a catalytic hydrogen peroxide sensor and enzyme-coupled glucose biosensors were developed as demonstrators. Hydrogen peroxide quantitation achieves a limit of detection of 0.713 mM and sensitivity of 78.37 mu A mM(-1) cm(-2), while glucose has a limit of detection of 0.111 mM and sensitivity of 12.68 mu A mM(-1) cm(-2). This rapid process allows an iterative design-build-test cycle in under 2 hours. The upfront cost to set up the system is less than USD 520, with each device costing less than USD 0.12, making this manufacturing process suitable for low-resource laboratories or classroom settings.
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| 3. |
- Barry, Antonia, et al.
(författare)
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Investigating the effects of arginine methylation inhibitors on microdissected brain tumour biopsies maintained in a miniaturised perfusion system
- 2023
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Ingår i: Lab on a Chip. - 1473-0197 .- 1473-0189. ; 23:11, s. 2664-2682
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Tidskriftsartikel (refereegranskat)abstract
- Arginine methylation is a post-translational modification that consists of the transfer of one or two methyl (CH3) groups to arginine residues in proteins. Several types of arginine methylation occur, namely monomethylation, symmetric dimethylation and asymmetric dimethylation, which are catalysed by different protein arginine methyltransferases (PRMTs). Inhibitors of PRMTs have recently entered clinical trials to target several types of cancer, including gliomas (NCT04089449). People with glioblastoma (GBM), the most aggressive form of brain tumour, are among those with the poorest quality of life and likelihood of survival of anyone diagnosed with cancer. There is currently a lack of (pre)clinical research on the possible application of PRMT inhibitors to target brain tumours. Here, we set out to investigate the effects of clinically-relevant PRMT inhibitors on GBM biopsies. We present a new, low-cost, easy to fabricate perfusion device that can maintain GBM tissue in a viable condition for at least eight days post-surgical resection. The miniaturised perfusion device enables the treatment of GBM tissue with PRMT inhibitors ex vivo, and we observed a two-fold increase in apoptosis in treated samples compared to parallel control experiments. Mechanistically, we show thousands of differentially expressed genes after treatment, and changes in the type of arginine methylation of the RNA binding protein FUS that are consistent with hundreds of differential gene splicing events. This is the first time that cross-talk between different types of arginine methylation has been observed in clinical samples after treatment with PRMT inhibitors.
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| 4. |
- Hauser, Janosch, et al.
(författare)
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A microfluidic device for TEM sample preparation
- 2020
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 20:22, s. 4186-4193
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Tidskriftsartikel (refereegranskat)abstract
- Transmission electron microscopy (TEM) allows for visualizing and analyzing viral particles and has become a vital tool for the development of vaccines and biopharmaceuticals. However, appropriate TEM sample preparation is typically done manually which introduces operator-based dependencies and can lead to unreliable results. Here, we present a capillary-driven microfluidic single-use device that prepares a TEM grid with minimal and non-critical user interaction. The user only initiates the sample preparation process, waits for about one minute and then collects the TEM grid, ready for imaging. Using Adeno-associated virus (AAV) particles as the sample and NanoVan (R) as the stain, we demonstrate microfluidic consistency and show that the sample preparation quality is sufficient for automated image analysis. We further demonstrate the versatility of the microfluidic device by preparing two protein complexes for TEM investigations using two different stain types. The presented TEM sample preparation concept could alleviate the problems associated with human inconsistency in manual preparation protocols and allow for non-specialists to prepare TEM samples.
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| 5. |
- Iseri, Emre, et al.
(författare)
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Digital dipstick: miniaturized bacteria detection and digital quantification for the point-of-care
- 2020
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 20:23, s. 4349-4356
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Tidskriftsartikel (refereegranskat)abstract
- Established digital bioassay formats, digital PCR and digital ELISA, show extreme limits of detection, absolute quantification and high multiplexing capabilities. However, they often require complex instrumentation, and extensive off-chip sample preparation. In this study, we present a dipstick-format digital biosensor (digital dipstick) that detects bacteria directly from the sample liquid with a minimal number of steps: dip, culture, and count. We demonstrate the quantitative detection of Escherichia coli (E. coli) in urine in the clinically relevant range of 102 –105 CFU ml−1 for urinary tract infections. Our format shows 89% sensitivity to detect E. coli in clinical urine samples (n = 28) when it is compared to plate culturing (gold standard). The significance and uniqueness of this diagnostic test format is that it allows a non-trained operator to detect urinary tract infections in the clinically relevant range in the home setting.
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| 6. |
- Kumar, Tharagan, et al.
(författare)
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Lab-in-a-fiber-based integrated particle separation and counting
- 2023
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 23, s. 2286-
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Tidskriftsartikel (refereegranskat)abstract
- An all-fiber integrated device capable of separating and counting particles is presented. A sequence of silica fiber capillaries with various diameters and longitudinal cavities are used to fabricate the component for size-based elasto-inertial passive separation of particles followed by detection in an uninterrupted continuous flow. Experimentally, fluorescent particles of 1 μm and 10 μm sizes are mixed in a visco-elastic fluid and fed into the all-fiber separation component. The particles are sheathed by an elasticity enhancer (PEO - polyethylene oxide) to the side walls. Larger 10 μm particles migrate to the center of the silica capillary due to the combined inertial lift force and elastic force, while the smaller 1 μm particles are unaffected, and exit from a side capillary. A separation efficiency of 100% for the 10 μm and 97% for the 1 μm particles is achieved at a total flow rate of 50 μL min−1. To the best of our knowledge, this is the first time effective inertial-based separation has been demonstrated in circular cross-section microchannels. In the following step, the separated 10 μm particles are routed through another all-fiber component for counting and a counting throughput of ∼1400 particles per min is demonstrated. We anticipate the ability to combine high throughput separation and precise 3D control of particle position for ease of counting will aid in the development of advanced microflow cytometers capable of particle separation and quantification for various biomedical applications.
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| 7. |
- Lee, Amos C., et al.
(författare)
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OPENchip : an on-chip in situ molecular profiling platform for gene expression analysis and oncogenic mutation detection in single circulating tumour cells
- 2020
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 20:5, s. 912-922
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Tidskriftsartikel (refereegranskat)abstract
- Liquid biopsy holds promise towards practical implementation of personalized theranostics of cancer. In particular, circulating tumour cells (CTCs) can provide clinically actionable information that can be directly linked to prognosis or therapy decisions. In this study, gene expression patterns and genetic mutations in single CTCs are simultaneously analysed by strategically combining microfluidic technology and in situ molecular profiling technique. Towards this, the development and demonstration of the OPENchip (On-chip Post-processing ENabling chip) platform for single CTC analysis by epithelial CTC enrichment and subsequent in situ molecular profiling is reported. For in situ molecular profiling, padlock probes that identify specific desired targets to examine biomarkers of clinical relevance in cancer diagnostics were designed and used to create libraries of rolling circle amplification products. We characterize the OPENchip in terms of its capture efficiency and capture purity, and validate the probe design using different cell lines. By integrating the obtained results, molecular analyses of CTCs from metastatic breast cancer (HER2 (ERBB2) gene expression and PIK3CA mutations) and metastatic pancreatic cancer (KRAS gene mutations) patients were demonstrated without any off-chip processes. The results substantiate the potential implementation of early molecular detection of cancer through sequencing-free liquid biopsy.
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| 8. |
- Marques, Filipe, et al.
(författare)
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Semi-automated preparation of fine-needle aspiration samples for rapid on-site evaluation
- 2022
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 22, s. 2192-2199
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Tidskriftsartikel (refereegranskat)abstract
- Rapid on-site evaluation (ROSE) significantly improves the diagnostic yield of fine needle aspiration (FNA) samples but critically depends on the skills and availability of cytopathologists. Here, we introduce a portable device for semi-automated sample preparation for ROSE. In a single platform, the device combines a smearing tool and a capillary-driven chamber for staining FNA samples. Using a human pancreatic cancer cell line (PANC-1) and liver, lymph node, and thyroid FNA model samples, we demonstrate the capability of the device to prepare samples for ROSE. By minimizing the equipment needed in the operating room, the device may simplify the performance of FNA sample preparation and lead to a wider implementation of ROSE.
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| 9. |
- Olofsson, Karl, et al.
(författare)
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Acoustic separation of living and dead cells using high density medium
- 2020
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 20:11, s. 1981-1990
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Tidskriftsartikel (refereegranskat)abstract
- The acoustic radiation force, originating from ultrasonic standing waves and utilized in numerous cell oriented acoustofluidic applications, is dependent on the acoustic contrast factor which describes the relationship between the acousto-mechanical properties of a particle and its surrounding medium. The acousto-mechanical properties of a cell population are known to be heterogeneously distributed but are often assumed to be constant over time. In this paper, we use microchannel acoustophoresis to show that the cell state within a cell population, in our case living and dead cells, influences the mechanical phenotype. By investigating the trapping location of viable and dead K562, MCF-7 and A498 cells as a function of the suspension medium density, we observed that beyond a specific medium density the viable cells were driven to the pressure anti-node while the dead cells were retained in the pressure node. Using this information, we were able to calculate the effective acoustic impedance of viable K562 and MCF-7 cells. The spatial separation between viable and dead cells along the channel width demonstrates a novel acoustophoresis approach for binary separation of viable and dead cells in a cell-size independent and robust manner.
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| 10. |
- Ovdiichuk, Olga, et al.
(författare)
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Implementation of iMiDEV™, a new fully automated microfluidic platform for radiopharmaceutical production
- 2021
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 21:11, s. 2272-2282
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Tidskriftsartikel (refereegranskat)abstract
- iMiDEV™ microfluidic system is a new automated tool for a small-scale production of radiopharmaceuticals. This new radiochemistry module utilizes microfluidic cassettes capable of producing diversified radiopharmaceuticals in liquid phase reactions in an automated synthesizer. The user interface is intuitive and designed to give the operator all the information required and to allow driving the synthesis either manually or fully automatically. In this work, we have demonstrated liquid phase reaction and presented the first results of an efficient fully automated [18F]NaF radiosynthesis on the iMiDEV™ platform. Different parameters such as a type of cyclotron targets, initial activity, concentration and volume of the fluoride-18 targetry have been investigated in order to elaborate the optimised radiolabelling of the ligand. Single and double sodium [18F]fluoride synthesis procedures have been successfully developed using two chambers of the cassette. A single-dose of radiotracer was produced in an average radiochemical yield of 87% (decay corrected) within 8 min and quality control tests were performed as per European Pharmacopoeia.
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