Journal: Nanoscale

Article Title: Quantification of nanoscale forces in lectin-mediated bacterial attachment and uptake into giant liposomes.

doi: 10.1039/d0nr07726g

Figure Lengend Snippet: Fig. 3 Strong attachment, high unbinding steps and pulled membrane tethers between LecA-coated AFM tips and Gb3-functionalized GUVs. (A) A SEM image of the used AFM tips (scale bar: 9 µm) shows a pyramid tip with a hemisphere end which is of similar size to a PA bacterium (scale bar in zoomed area: 900 nm). (B) Representative f–d curves for albumin-coated tips (blue box) and LecA-coated tips (red box) and analyzed parameters: detachment force (Fd), detachment work (Wd), the height (unbinding force) and position (pulling length) of unbinding steps. Comparison of (C) the detachment force and (D) the detachment work for albumin- and LecA-coated tips interacting with Gb3-positive GUVs (GUV+) or Gb3-negative GUVs (GUV−). Presence of LecA on tips and Gb3 in the GUV membrane led to a significant increase in detachment force and work (the total number of curves for albumin- and LecA-coated tips is 85 and 60, respectively; ****: P-Value < 0.0001 using Mann–Whitney-U-test). (E) The unbinding force versus pulling length graph for LecA-coated tips interacting with GUV−and GUV+ vesicles. Zoomed area in (E) illustrates the unbinding steps with lower pulling length (<250 nm). (F) Membrane deformation of a GUV during retraction of LecA-coated tips recorded as z-stack with a confocal microscope. Green and red arrows point to the catenoid shape and membrane tether formation, respectively. The blue hemisphere indicates the tip position (scale bar: 5 µm).

Article Snippet: All force measurements have been performed using a NanoWizard 3 and a CellHesion 200 (JPK BioAFM, Bruker Nano GmbH) integrated with an inverted Nikon Ti microscope equipped with a 40× water immersion objective and an Intensilight epifluorescence illuminator.

Techniques: Membrane, Comparison, MANN-WHITNEY, Microscopy