Snl a probes

For AFM imaging, 100 µL of the vesicle suspensions at 1 mM of DOPC and DOPC doped with 20 mol% DOPS were deposited on freshly cleaved mica (1 cm², muscovite mica, grade V1 from Tedpella) and left for 1 h at room temperature (25 °C) to ensure the formation of lipid bilayer. Afterwards, the mica surfaces were rinsed thoroughly with HEPES buffer to remove the excess of unbroken liposomes. The AFM imaging of lipid bilayer was performed in HEPES buffer at room temperature (25 °C) using a JPK Nanowizard Ultraspeed AFM (Bruker, Karlsruhe, Germany) in amplitude modulation AFM (AM-AFM) with low force settings (80–90% of the free amplitude A ~ 6 nm). Gold coated silicon nitride Lever (SNL-A) probes (Bruker, Santa Barbara, CA) with a nominal spring constant of 0.35 N/m and a tip radius of 2 nm have been used. Afterwards, 50 µl of Hsp70 solution (1 mg/ml) was added onto the lipid bilayer to get a final Hsp70 concentration of 100 µg/ml in the fluid AFM cell and the adsorption mechanism was monitored over approximately 24 h.
AFM images of 5 µm x 5 µm (512 × 512 pixels) were taken at the scan rate of 1 Hz. The height images were processed using the JPK Data Processing software.