Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Wednesday Speaker Abstracts

CORRELATIVE AFM-CONFOCAL MECHANOTYPING OF THE E.COLI ENVELOPE Andre Körnig 1 ; Supriya V Bhat 2 ; Tanya E Dahms 2 ; Thomas Henze 1 ; 1 Bruker Nano GmbH, BioAFM, Berlin, Germany 2 University of Regina, Chemistry and Biochemistry, Regina, SK, Canada We established a multiparametric correlative workflow that integrates quantitative-imaging atomic force microscopy (AFM) with confocal microscopy to map nanoscale topography, stiffness, and adhesion of live bacteria while simultaneously tracking fluorescent reporters, which enabled minimally perturbative, real-time mechanotyping at piconewton sensitivity. Fast force-mapping resolved subcellular mechanical heterogeneity across whole cells and supported longitudinal measurements during environmental or antimicrobial challenges, directly linking outer-envelope remodelling to local adhesion landscapes and cell-scale stiffness. Leveraging high-speed tip-scanning advances, we demonstrate high lateral and vertical sub-nanometer accuracy on tall (>1 µm) specimens while capturing rapid envelope dynamics that preceded phenotypic change. Applied to Escherichia coli, correlative AFM–confocal imaging uncovered coordinated changes in roughness, elasticity, and adhesion that reported on supramolecular outer-membrane organization, including lipoproteins and outer membrane proteins and its coupling to morphogenesis and surface engagement - key determinants of early biofilm formation. The assay quantified these mechanical signatures in situ and in real time, providing a robust basis for comparing strain-dependent mechanotypes and for screening anti-adhesive or envelope-targeting agents relevant to infection settings [1]. To demonstrate biological specificity, we challenged cells with sub-lethal 2,4-dichlorophenoxyacetic acid (2,4-D). Within seconds, divisome proteins FtsZ/FtsA relocalized and septation arrested; over longer exposures, SOS activation and oxidative-stress–linked DNA damage emerged, coincident with time-dependent shifts in surface roughness, elasticity, and adhesion captured by AFM. These results mechanistically connected xenobiotic-induced dissipation of membrane potential and division inhibition to envelope remodeling measured by force mapping, establishing a unified picture of how chemical stress rewires bacterial mechanics, adhesion, and growth [2].1. Bhat, S. V.; Sultana, T.; Körnig, A.; McGrath, S.; Shahina, Z.; Dahms, T. E. S. Correlative Atomic Force Microscopy Quantitative Imaging-Laser Scanning Confocal Microscopy Quantifies the Impact of Stressors on Live Cells in Real-Time. Sci Rep 2018, 8 (1), 8305. 2. Bhat, S. V.; Kamencic, B.; Körnig, A.; Shahina, Z.; Dahms, T. E. S. Exposure to Sub-Lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia Coli. Front. Microbiol. 2018, 9, 44.

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