• Effect of caffeine and other xanthines on liver sinusoidal endothelial cell ultrastructure 

      Mao, Hong; Szafranska, Karolina; Kruse, Larissa Dorothea; Holte, Christopher Florian; Wolfson, Deanna; Ahluwalia, Balpreet Singh; Whitchurch, Cynthia B.; Cole, Louise; Lockwood, Glen P.; Diekmann, Robin; Le Couteur, David; Cogger, Victoria C.; McCourt, Peter Anthony (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-17)
      Xanthines such as caffeine and theobromine are among the most consumed psychoactive stimulants in the world, either as natural components of cofee, tea and chocolate, or as added ingredients. The present study assessed if xanthines affect liver sinusoidal endothelial cells (LSEC). Cultured primary rat LSEC were challenged with xanthines at concentrations typically obtained from normal consumption of ...
    • Endocytic motif on a biotin-tagged hiv-1 env modulates the co-transfer of env and gag during cell-to-cell transmission 

      Barría, María Inés; Alvarez, Raymond A.; Law, Kenneth; Wolfson, Deanna; Huser, Thomas; Chen, Benjamin K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-31)
      During HIV-1 transmission through T cell virological synapses, the recruitment of the envelope (Env) glycoprotein to the site of cell–cell contact is important for adhesion and for packaging onto nascent virus particles which assemble at the site. Live imaging studies in CD4 T cells have captured the rapid recruitment of the viral structural protein Gag to VSs. We explored the role of endocytic ...
    • Label-free superior contrast with c-band ultra-violet extinction microscopy 

      Wolfson, Deanna; Opstad, Ida Sundvor; Hansen, Daniel Henry; Mao, Hong; Ahluwalia, Balpreet Singh; Ströhl, Florian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-03)
      In 1934, Frits Zernike demonstrated that it is possible to exploit the sample’s refractive index to obtain superior contrast images of biological cells. The refractive index contrast of a cell surrounded by media yields a change in the phase and intensity of the transmitted light wave. This change can be due to either scattering or absorption caused by the sample. Most cells are transparent at visible ...
    • Multi-color imaging of sub-mitochondrial structures in living cells using structured illumination microscopy 

      Opstad, Ida Sundvor; Wolfson, Deanna; Øie, Cristina Ionica; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-18)
      The dimensions of mitochondria are close to the diffraction limit of conventional light microscopy techniques, making the complex internal structures of mitochondria unresolvable. In recent years, new fluorescence-based optical imaging techniques have emerged, which allow for optical imaging below the conventional limit, enabling super-resolution (SR). Possibly the most promising SR and diffraction-limited ...
    • Multi-modal chip-based fluorescence and quantitative phase microscopy for studying inflammation in macrophages 

      Dubey, Vishesh; Ahmad, Azeem; Singh, Rajwinder; Wolfson, Deanna; Basnet, Purusotam; Acharya, Ganesh; Mehta, Dalip Singh; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-24)
      Total internal reflection fluorescence (TIRF) microscopy benefits from high-sensitivity, low background noise, low photo-toxicity and high-contrast imaging of sub-cellular structures close to the membrane surface. Although, TIRF microscopy provides high-contrast imaging it does not provide quantitative information about morphological features of the biological cells. Here, we propose an integrated ...
    • Nanoscopy of bacterial cells immobilized by holographic optical tweezers 

      Diekmann, Robin; Wolfson, Deanna; Spahn, Christoph; Heilemann, Mike; Schuttpelz, Mark; Huser, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-13)
      Imaging non-adherent cells by super-resolution far-field fluorescence microscopy is currently not possible because of their rapid movement while in suspension. Holographic optical tweezers (HOTs) enable the ability to freely control the number and position of optical traps, thus facilitating the unrestricted manipulation of cells in a volume around the focal plane. Here we show that immobilizing ...
    • Quantification of the NA dependent change of shape in the image formation of a z-polarised fluorescent molecule using vectorial diffraction simulations 

      Ströhl, Florian; Bruggeman, Ezra; Rowlands, Christopher; Wolfson, Deanna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-19)
      The point spread function of a fixed fluorophore with its dipole axis colinear to the optical axis appears donut-shaped when seen through a microscope, and its light distribution in the pupil plane is radially polarized. Yet other techniques, such as photolithography, report that this same light distribution in the pupil plane appears as a solid spot. How can this same distribution lead to a spot ...
    • Quantitative assessment of morphology and sub-cellular changes in macrophages and trophoblasts during inflammation 

      Singh, Rajwinder; Dubey, Vishesh; Wolfson, Deanna; Ahmad, Azeem; Butola, Ankit; Acharya, Ganesh; Singh Mehta, Dalip; Basnet, Purusotam; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-12)
      In pregnancy during an inflammatory condition, macrophages present at the feto-maternal junction release an increased amount of nitric oxide (NO) and pro-inflammatory cytokines such as TNF-α and INF-γ, which can disturb the trophoblast functions and pregnancy outcome. Measurement of the cellular and sub-cellular morphological modifications associated with inflammatory responses are important in order ...
    • Quantitative phase microscopy of red blood cells during planar trapping and propulsion 

      Ahmad, Azeem; Dubey, Vishesh; Singh, Vijay; Tinguely, Jean-Claude; Øie, Cristina Ionica; Wolfson, Deanna; Mehta, Dalip Singh; So, Peter T. C.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-22)
      Red blood cells (RBCs) have the ability to undergo morphological deformations during microcirculation, such as changes in surface area, volume and sphericity. Optical waveguide trapping is suitable for trapping, propelling and deforming large cell populations along the length of the waveguide. Bright field microscopy employed with waveguide trapping does not provide quantitative information about ...
    • Structured Illumination Microscopy of Biological Structures 

      Wolfson, Deanna; Villegas, Luis; Opstad, Ida Sundvor; Birgisdottir, Åsa birna; Øie, Cristina Ionica; Ahluwalia, Balpreet Singh (Conference object; Konferansebidrag, 2018)
      <p>Resolution in optical microscopy has long been limited to the Abbe diffraction limit, i.e. about 250 nm laterally for visible wavelengths on a very good microscope. In the last two decades several techniques have been devised to circumvent this limit: an achievement which was recognized with the 2014 Nobel Prize in Chemistry. Structured Illumination Microscopy (SIM) was the first of these techniques ...
    • A transparent waveguide chip for versatile total internal reflection fluorescence-based microscopy and nanoscopy 

      Priyadarshi, Anish; Wolfson, Deanna; Ahmad, Azeem; Jayakumar, Nikhil; Dubey, Vishesh Kumar; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh; Murugan, Ganapathy Senthil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-20)
      Total internal reflection fluorescence (TIRF) microscopy is an imaging technique that, in comparison to confocal microscopy, does not require a trade-off between resolution, speed, and photodamage. Here, we introduce a waveguide platform for chip-based TIRF imaging based on a transparent substrate, which is fully compatible with sample handling and imaging procedures commonly used with a standard ...
    • Two-dimensional TIRF-SIM–traction force microscopy (2D TIRF-SIM-TFM) 

      Barbieri, Liliana; Colin-York, Huw; Korobchevskaya, Kseniya; Li, Di; Wolfson, Deanna; Karedla, Narain; Schneider, Falk; Ahluwalia, Balpreet Singh; Seternes, Tore; Dalmo, Roy Ambli; Dustin, Michael L.; Li, Dong; Fritzsche, Marco (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-12)
      Quantifying small, rapidly evolving forces generated by cells is a major challenge for the understanding of biomechanics and mechanobiology in health and disease. Traction force microscopy remains one of the most broadly applied force probing technologies but typically restricts itself to slow events over seconds and micron-scale displacements. Here, we improve >2-fold spatially and >10-fold temporally ...
    • Uptake and Degradation of Bacteriophages by Liver Sinusoidal Endothelial Cells 

      Wolfson, Deanna; Øie, Cristina Ionica; Yasunori, Tanji; Dumitriu, Gianina; McCourt, Peter Anthony; Sørensen, Karen Kristine; Smedsrød, Bård; Ahluwalia, Balpreet Singh (Conference object; Konferansebidrag, 2018)
      <p>Bacteriophages (briefly, “phages”) are viruses which target bacteria, and are non-infectious to eukaryotic cells. It is estimated that more than 30 billion phages cross into the human body from the gut each day1, and eventually need to be cleared from the blood circulation. The liver plays a central role in pathogen clearance, and liver sinusoidal endothelial cells (LSECs), which form the lining ...