(515c) Interactions between AFM Tips and Biomembranes Via Multiscale Molecular Modeling

We study computationally the critical interactions between an Atomic Force Microscopy (AFM) tip and lipid membranes, a pivotal aspect in the advancement of nanoscale lipid constructs for applications in drug delivery systems and biosensors. We introduce a model that elucidates the complex molecular mechanisms underpinning the AFM tip-lipid interaction. The model comprises a multi-bilayer 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) lipid system on a substrate and a pyramidal-shaped amorphous silica Afm tip. Our study delves into the intricate forces at play at the lipid membrane surface during penetration, and the energy landscape that governs the mechanically induced rupture of lipid bilayers during AFM tip indentation. Furthermore, we extend our investigation to examine the local mechanics, the packing, and the size-dependent mechanics of the system. These phenomena are explored using coarse-grained MARTINI molecular dynamics simulation. The insights derived from this study are anticipated to significantly influence the future design of lipid-based nanoscale constructs.