Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Monday Speaker Abstracts

MECHANICAL PROPERTIES OF ESCHERICHIA COLI ENVELOPE, AND EFFORTS TO OBSERVE THESE IN INFECTION-RELEVANT, HOST-LIKE INVIRONMENTS Teuta Pilizota ; Saheli Mitra; Smitha Hegde; Pietro Cicuta University of Cambridge, Department of Physics, Cambrdige, United Kingdom A bacterial cell envelope is a unique active material whose mechanical properties are arguably not yet understood despite decades of active research. To decipher how the cell envelope dissipates energy and resists deformation, we place individual Escherichia coli cells under constant, long-term volumetric strain. For the purpose, we created an E.coli mutant with deletion of its seven mechanosensitive channels, and we demonstrate that under hypoosmotic downshocks of increasing magnitudes, the average cell volume increases and does not recover the characteristic response of the wild type. After a few hours of sustained volume expansion cells exhibit delayed-lysis and slow plastic deformation. We propose a mathematical model of the time-dependent response of dying cells to constant, high volumetric strain caused by the downshocks that describes the mechanical properties of the E.coli envelope. Next, we wish to study cell envelope mechanics that resemble sinus environment of a human host. Such environment is ripe with multi-scale interactions, and numerous physical and biological factors involved. We show our efforts to mimic such environment through maintaining epithelial cells under constant flow under a microscope and to characterise the rheological properities of such environment, all before we introduce bacterial cells to it.

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