Composition-dependent disruption pathways of supported lipid bilayers by methyl-β-cyclodextrin: A multimodal AFM, nanomechanical, and QCM-D study.

We investigated the effects of methyl-β-cyclodextrin (MβCD) on supported lipid bilayers (SLBs) using a combined approach of Atomic Force Microscopy (AFM) imaging, force-distance (F-D) measurements, and Quartz Crystal Microbalance with Dissipation (QCM-D). This multimodal approach allowed simultaneous assessment of mechanical and mass changes, revealing disruption pathways that depend strongly on membrane composition. AFM imaging showed time-dependent defect nucleation, with cholesterol-containing bilayers exhibiting the most extensive damage. Force-distance curves quantified across POPC, POPC/POPE (1:1), POPC/DPPC (1:1), and POPC/Chol (7:3) bilayers demonstrate that shifts in median rupture force and mechanical heterogeneity can be decoupled. Pure POPC bilayers displayed mild softening, POPC/DPPC (1:1) bilayers preserved mechanical resilience, and POPC/POPE (1:1) bilayers underwent pronounced destabilization with increased heterogeneity. Cholesterol-containing bilayers retained resistance to penetration despite the selective removal of weak regions. Statistical evaluation confirmed these trends and highlighted the mechanical transitions. Overall, our results demonstrate that MβCD-induced disruption is governed by lipid composition, phase behavior, and intrinsic membrane stress.