Glassy Dynamics as a Predictive Framework for Lipid Exchange Across Membranes

Lipid exchange between membranes is fundamental to biological function and technological applications, from drug delivery and vesicle trafficking to the design of biomimetic materials. Yet, quantitative prediction of both activation energies and timescales has remained elusive due to complex energy landscapes. Here, we present a thermodynamic-kinetic framework inspired by glassy dynamics to address this challenge. Using a single, experimentally accessible parameter-the thermal expansion coefficient of lipid vesicles-we apply the Collective Small Displacements (CSD) model to predict activation energies and transfer timescales without adjustable parameters. Our label-free quartz crystal microbalance experiments validate these predictions across multiple lipid systems. We demonstrate that lipid exchange proceeds through rare, cooperative molecular events analogous to those governing relaxation in amorphous materials. By connecting a simple equilibrium thermodynamic property to interfacial transport dynamics, this work provides a versatile predictive tool for engineering lipid-based materials and transport kinetics at the nanoscale, with broad implications for soft matter physics, synthetic biology, and nanobiotechnology.