The localization of surfaces inhomogeneities is central to many areas of technology, chemistry and biology, ranging from surface defects in industry to the identification and screening of early bio-defects inside cells. The development of methods that enable direct, sensitive, and rapid detection of those inhomogeneities is both relevant and timely. To address this challenge, we developed a far-field nanoimaging method to detect the presence of surface's nanodefects that modify the signal emitted by gold nanoparticles (AuNPs) under laser irradiation. Our technique is based on the formation of hot spots due to the confinement of light in the proximity of the AuNP, whose positions depend on the polarization direction of the incident beam. An inhomogeneity is detected as an increase in the intensity collected from the hot spots when a laser beam is orbiting the nanoparticle and the incident polarization direction of the laser beam is changed periodically.
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Nano Lett
January 2025
Regensburg Center for Ultrafast Nanoscopy (RUN) and Department of Physics, University of Regensburg, 93040 Regensburg, Germany.
Detecting electromagnetic radiation scattered from a tip-sample junction has enabled overcoming the diffraction limit and started the flourishing field of polariton nanoimaging. However, most techniques only resolve amplitude and relative phase of the scattered radiation. Here, we utilize field-resolved detection of ultrashort scattered pulses to map the dynamics of surface polaritons in both space and time.
View Article and Find Full Text PDFACS Nano
January 2025
Aix Marseille Univ, INSERM, SSA, MCT, 27 Bd Jean Moulin, Marseille 13005, France.
Bacterial resistance is a major public health challenge. In Gram-negative bacteria, the synergy between multidrug efflux pumps and outer membrane impermeability determines the intracellular concentration of antibiotics. Consequently, it also dictates antibiotic activity on their respective targets.
View Article and Find Full Text PDFGigascience
January 2024
Department of Health Technology, Technical University of Denmark, Kongens Lyngby 2800, Denmark.
Background: Corneocyte surface nanoscale topography (nanotexture) has recently emerged as a potential biomarker for inflammatory skin diseases, such as atopic dermatitis (AD). This assessment method involves quantifying circular nano-size objects (CNOs) in corneocyte nanotexture images, enabling noninvasive analysis via stratum corneum (SC) tape stripping. Current approaches for identifying CNOs rely on computer vision techniques with specific geometric criteria, resulting in inaccuracies due to the susceptibility of nano-imaging techniques to environmental noise and structural occlusion on the corneocyte.
View Article and Find Full Text PDFCancer Cell
January 2025
Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY, USA. Electronic address:
T cell-based immunotherapies have demonstrated effectiveness in treating diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL) but predicting response and understanding resistance remains a challenge. To address this, we developed syngeneic models reflecting the genetics, epigenetics, and immunology of human FL and DLBCL. We show that EZH2 inhibitors reprogram these models to re-express T cell engagement genes and render them highly immunogenic.
View Article and Find Full Text PDFNat Commun
December 2024
School of Chemistry, Cardiff University, Park Place, Cardiff, UK.
Advances in X-ray crystallography and cryogenic electron microscopy (cryo-EM) offer the promise of elucidating functionally relevant conformational changes that are not easily studied by other biophysical methods. Here we show that 3D variability analysis (3DVA) of the cryo-EM map for wild-type (WT) human asparagine synthetase (ASNS) identifies a functional role for the Arg-142 side chain and test this hypothesis experimentally by characterizing the R142I variant in which Arg-142 is replaced by isoleucine. Support for Arg-142 playing a role in the intramolecular translocation of ammonia between the active site of the enzyme is provided by the glutamine-dependent synthetase activity of the R142 variant relative to WT ASNS, and MD simulations provide a possible molecular mechanism for these findings.
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