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| 2. |
- Deschout, Hendrik, et al.
(författare)
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Straightforward FRAP for quantitative diffusion measurements with a laser scanning microscope
- 2010
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Ingår i: Optics Express. - 1094-4087. ; 18:22, s. 22886-22905
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Tidskriftsartikel (refereegranskat)abstract
- Confocal or multi-photon laser scanning microscopes are convenient tools to perform FRAP diffusion measurements. Despite its popularity, accurate FRAP remains often challenging since current methods are either limited to relatively large bleach regions or can be complicated for non-specialists. In order to bring reliable quantitative FRAP measurements to the broad community of laser scanning microscopy users, here we have revised FRAP theory and present a new pixel based FRAP method relying on the photo bleaching of rectangular regions of any size and aspect ratio. The method allows for fast and straightforward quantitative diffusion measurements due to a closed–form expression for the recovery process utilizing all available spatial and temporal data. After a detailed validation, its versatility is demonstrated by diffusion studies in heterogeneous biopolymer mixtures.
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| 3. |
- Fransson, Sophia, 1979, et al.
(författare)
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Modelling and confocal microscopy of biopolymer mixtures in confined geometries
- 2010
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 6:12, s. 2713-2722
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of a phase separating and gelling biopolymer mixture (gelatin-maltodextrin) is strongly affected not only by thermodynamic conditions, but also by the presence of a restricted geometry. Phase separation within droplets is analysed using confocal laser scanning microscopy and image analysis by varying concentration (4% gelatin and 4%-7.3% maltodextrin), quench temperature (10 degrees C to 25 degrees C) and droplet diameters (10 mu m-120 mu m). The effects of confinement as well as quench temperature increase with increasing maltodextrin concentration in 120 mu m sized droplets. In small droplets below 20 mu m, the confinement and surface dominate the microstructure. The trends observed show good agreement with predictions of the elastic Lennard-Jones (ELJ) model, adapted to handle confinement, that is solved via conventional molecular dynamics. A one-dimensional spin-chain with variable bond length is furthermore introduced and shown to capture a number of qualitative behaviors. The findings reveal that the confined biopolymer mixture can be characterized by the very few parameters of the ELJ model, which incorporates the basic mechanism of short range attraction (collapse, crystallization) versus long range elastic repulsion (osmotic penalty). Accordingly, the study suggests that the model provides a handle towards the morphological design of binary polymer mixtures in microcapsules, droplets or other geometries of well defined size and shape.
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| 4. |
- Nilsson, Peter, et al.
(författare)
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Structural typing of systemic amyloidoses by luminescent-conjugated polymer spectroscopy.
- 2010
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Ingår i: The American journal of pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 176:2, s. 563-574
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Tidskriftsartikel (refereegranskat)abstract
- Most systemic amyloidoses are progressive and lethal, and their therapy depends on the identification of the offending proteins. Here we report that luminescent-conjugated thiophene polymers (LCP) sensitively detect amyloid deposits. The heterodisperse polythiophene acetic acid derivatives, polythiophene acetic acid (PTAA) and trimeric PTAA, emitted yellow-red fluorescence on binding to amyloid deposits, whereas chemically homogeneous pentameric formic thiophene acetic acid emitted green-yellow fluorescence. The geometry of LCPs modulates the spectral composition of the emitted light, thereby reporting ligand-induced steric changes. Accordingly, a screen of PTAA-stained amyloid deposits in histological tissue arrays revealed striking spectral differences between specimens. Blinded cluster assignments of spectral profiles of tissue samples from 108 tissue samples derived from 96 patients identified three nonoverlapping classes, which were found to match AA, AL, and ATTR immunotyping. We conclude that LCP spectroscopy is a sensitive and powerful tool for identifying and characterizing amyloid deposits.
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| 7. |
- Wigenius, Jens, et al.
(författare)
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Protein biochips patterned by microcontact printing or by adsorption-soft lithography in two modes
- 2008
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Ingår i: Biointerphases. - : American Vacuum Society. - 1934-8630 .- 1559-4106. ; 3:3, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- Patterning of proteins is critical to protein biochips. Printing of layers of proteins is well established, as is adsorption of proteins to surfaces properly modified with surface chemical functionalities. The authors show that simple methods based on soft lithography stamps can be used to prepare functional antibody chips through both these routes. Both methods incorporate transfer of the stamp material poly(dimethylsiloxane) (PDMS) to the biochip, whether intended or not intended. The results indicate that microcontact printing of proteins always includes PDMS transfer, thereby creating a possibility of unspecific adsorption to a hydrophobic domain. © 2008 American Vacuum Society.
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