| 1. |
- Mikus, Maria, et al.
(författare)
-
Allergome-wide peptide microarrays enable epitope deconvolution in allergen-specific immunotherapy
- 2020
-
Ingår i: Journal of Allergy and Clinical Immunology. - : Mosby Inc.. - 0091-6749 .- 1097-6825.
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The interaction of allergens and allergen-specific IgE initiates the allergic cascade after crosslinking of receptors on effector cells. Antibodies of other isotypes may modulate such a reaction. Receptor crosslinking requires binding of antibodies to multiple epitopes on the allergen. Limited information is available on the complexity of the epitope structure of most allergens. Objectives: We sought to allow description of the complexity of IgE, IgG4, and IgG epitope recognition at a global, allergome-wide level during allergen-specific immunotherapy (AIT). Methods: We generated an allergome-wide microarray comprising 731 allergens in the form of more than 172,000 overlapping 16-mer peptides. Allergen recognition by IgE, IgG4, and IgG was examined in serum samples collected from subjects undergoing AIT against pollen allergy. Results: Extensive induction of linear peptide-specific Phl p 1– and Bet v 1–specific humoral immunity was demonstrated in subjects undergoing a 3-year-long AIT against grass and birch pollen allergy, respectively. Epitope profiles differed between subjects but were largely established already after 1 year of AIT, suggesting that dominant allergen-specific antibody clones remained as important contributors to humoral immunity following their initial establishment during the early phase of AIT. Complex, subject-specific patterns of allergen isoform and group cross-reactivities in the repertoires were observed, patterns that may indicate different levels of protection against different allergen sources. Conclusions: The study highlights the complexity and subject-specific nature of allergen epitopes recognized following AIT. We envisage that epitope deconvolution will be an important aspect of future efforts to describe and analyze the outcomes of AIT in a personalized manner.
|
|
| 2. |
- Fornell, Anna, et al.
(författare)
-
An intra-droplet particle switch for droplet microfluidics using bulk acoustic waves
- 2017
-
Ingår i: Biomicrofluidics. - : AIP Publishing. - 1932-1058. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- To transfer cell- and bead-assays into droplet-based platforms typically requires the use of complex microfluidic circuits, which calls for methods to switch the direction of the encapsulated particles. We present a microfluidic chip where the combination of acoustic manipulation at two different harmonics and a trident-shaped droplet-splitter enables direction-switching of microbeads and yeast cells in droplet microfluidic circuits. At the first harmonic, the encapsulated particles exit the splitter in the center daughter droplets, while at the second harmonic, the particles exit in the side daughter droplets. This method holds promises for droplet-based assays where particle-positioning needs to be selectively controlled.
|
|
| 3. |
|
|
| 4. |
- Ohlin, Mathias, 1984-, et al.
(författare)
-
Two-dimensional acoustic focusing of microparticles in two-phase droplet-based microfluidic systems for improved particle positioning within spherical droplets
- 2016
-
Konferensbidrag (refereegranskat)abstract
- We have fabricated a silicon-glass microfluidic two-phase droplet generator capable of generating sub 100-micrometer-sized (⌀ ൌ74 μm ± 2 μm) spherical droplets at rates up to hundreds of hertz (298 Hz ± 85 Hz). Furthermore, we have implemented a two-dimensional acoustic focusing technique into the device. Here, we show that applying the focusing to 10 μm sized polystyrene particles during the droplet generation step, results in a fourfold improvement of the particle positioning (centricity) within the generated droplets compared to the unactuated control. Finally, the efficiency of the system has been optimized by incorporating aluminum matching layers in the transducer design permitting biocompatible operational temperatures (<37°C).
|
|
| 5. |
- Ohlin, Mathias, 1984-, et al.
(författare)
-
Two-dimensional acoustic focusing of microparticles in two-phase droplet-based microfluidic systems increases particle detectability
- 2016
-
Ingår i: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016. - 9780979806490 ; , s. 713-714
-
Konferensbidrag (refereegranskat)abstract
- We have fabricated a silicon-glass two-phase droplet-based microfluidic system and implemented two-dimensional acoustic focusing prior to droplet generation as well as continuously throughout the whole system to increase particle detectability. Using acoustic focusing we have effectively minimized sedimentation of the encapsulated particles and thereby increased particle detectability by as much as 44% compared to unactuated operation of the system.
|
|
| 6. |
- Ohlin, Mathias, 1984-
(författare)
-
Ultrasonic Fluid and Cell Manipulation
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the last decade, ultrasonic manipulation has matured into an important tool with a wide range of applications, from fundamental cell biological research to clinical and industrial implementations. The contactless nature of ultrasound makes it possible to manipulate living cells in a gentle way, e.g., for positioning, sorting, and aggregation. However, when manipulating cells using ultrasound, especially using high acoustic amplitudes, a great deal of heat can be generated. This constitutes a challenge, since the viability of cells is dependent on a stable physiological temperature around 37°C. In this Thesis we present applications of ultrasonic manipulation of fluids, particles, and cells in temperature-controlled micrometer-sized devices fabricated using well established etching techniques, directly compatible with high-resolution fluorescence microscopy. Furthermore, we present ultrasonic manipulation in larger up to centimeter-sized devices optimized for fluid mixing and cell lysis. In the present work, two new ultrasonic manipulation platforms have been developed implementing temperature control. These platforms are much improved with increased performance and usability compared to previous platforms. Also, two new ultrasonic platforms utilizing low-frequency ultrasound for solubilization and cell lysis of microliter-volumed and milliliter-volumed samples have been designed and implemented. We have applied ultrasound to synchronize the interaction between large numbers of immune, natural killer cells, and cancer cells to study the cytotoxic response, on a single cell level. A heterogeneity was found among the natural killer cell population, i.e., some cells displayed high cytotoxic response while others were dormant. Furthermore, we have used temperature-controlled ultrasound to form up to 100, in parallel, solid cancer HepG2 tumors in a glass-silicon multi-well microplate. Next, we investigated the immune cells cytotoxic response against the solid tumors. We found a correlation between the number of immune cells compared to the size of the tumor and the cytotoxic outcome, i.e., if the tumor could be defeated. Finally, the effect of high acoustic pressure amplitudes in the MPa-range on cell viability has been studied in a newly developed platform optimized for long-term stable temperature control, independent on the applied ultrasound power. Lastly, we present two applications of ultrasonic fluid mixing and lysis of cells. One platform is optimized for small microliter-sized volumes in plastic disposable chips and another is optimized for large milliliter-sized volumes in plastic test tubes. The latter platform has been implemented for clinical sputum sample solubilization and cell lysis for genomic DNA extraction for subsequent pathogen detection
|
|
| 7. |
- Olofsson, Karl, et al.
(författare)
-
Acoustic formation of multicellular tumor spheroids enabling on-chip functional and structural imaging
- 2018
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 18:16, s. 2466-2476
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the complex 3D tumor microenvironment is important in cancer research. This microenvironment can be modelled in vitro by culturing multicellular tumor spheroids (MCTS). Key challenges when using MCTS in applications such as high-throughput drug screening are overcoming imaging and analytical issues encountered during functional and structural investigations. To address these challenges, we use an ultrasonic standing wave (USW) based MCTS culture platform for parallel formation, staining and imaging of 100 whole MCTS. A protein repellent amphiphilic polymer coating enables flexible production of high quality and unanchored MCTS. This enables high-content multimode analysis based on flow cytometry and in situ optical microscopy. We use HepG2 hepatocellular carcinoma, A498 and ACHN renal carcinoma, and LUTC-2 thyroid carcinoma cell lines to demonstrate (i) the importance of the ultrasound-coating combination, (ii) bright field image based automatic characterization of MTCS, (iii) detailed deep tissue confocal imaging of whole MCTS mounted in a refractive index matching solution, and (iv) single cell functional analysis through flow cytometry of single cell suspensions of disintegrated MTCS. The USW MCTS culture platform is customizable and holds great potential for detailed multimode MCTS analysis in a high-content manner.
|
|
