Title： Surface Nanomechanics of Bacteria under UV Radiation

Abstract: It is well established that UV radiation can inactivate bacteria by destroying DNA in the cell envelope, and maintaining the integrity of the cellular membrane. However, how UV radiation changes the surface properties and thus affects bacterial adhesion remain elusive. In this study, single-cell force spectroscopy is employed to examine the surface nanomechanics of Pseudomonas aeruginosa under UV exposure. It shows that P. aeruginosa became stiffer after UV radiation, and its adhesion to silicon surface decreases with rupture length increasing. Nanospring signatures in the retraction force curve become less with lower spring constant but more plateau signatures with higher rupture length appear. These facts indicate the unfolding of the 𝜶-helices of the pili. Besides, the worm-like chain force curves with higher contour length indicate the structural degradation of transmembrane proteins or surface macromolecules obstruction. Accordingly, the bacterial adhesion decreases after UV radiation.

DOI：doi.org/10.1002/macp.202300302