Surface nanoroughness impacts the formation and stability of supported lipid bilayers

Solid supported lipid bilayers (SLBs) are excellent platforms for studying the biophysical properties of cell membranes, as well as versatile biomimetic films for biotechnology applications. Among the existing approaches used to form SLBs, vesicle fusion and rupture onto solid supports is the most commonly employed one owing to its straightforward procedure. SLBs are typically formed on atomically flat and very hydrophilic surfaces, overlooking the influence of roughness and topography on membrane formation and organization. As a matter of fact, lipid bilayers in vivo are corrugated at the nanoscale level, as a result of interactions with proteins, fibrils, and other components within the intracellular and extracellular environment. Fundamental studies of the effect of surface roughness on SLBs are scarce and restricted to few contributions, where nanoroughness has shown to affect lipid mobility by a 5-fold decrease and inhibit domain growth in phase-separated membranes. In this work, the impact of nanoroughness on the formation and stability of SLBs onto SiO2 surfaces with different degrees of vertical and lateral surface roughness is studied. Combining quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy with force spectroscopy (AFM-FS), it is shown that nanoroughness affects the formation of SLBs by increasing the activation energy of vesicle fusion, rupture and spreading, and weakens the stability and lateral organization of the formed SLBs.