Pore Dynamics of Lipid Vesicles under Light-Induced Osmotic Stress

Understanding the physical mechanisms governing the response of lipid vesicles under an osmotic imbalance is crucial not only for advancing our knowledge of osmoregulation in living cells but also for guiding the design of biomedical vesicular systems. When placed under osmotic stress, lipid vesicles exhibit a variety of responses, from simple engorgement, to swelling with eventual pore formation, to the only recently observed irreversible explosion triggered by photoreactions. Here, we present a unifying model that incorporates all of these dynamic responses by elucidating the associated energy landscape of vesicle outcomes. We demonstrate the essential, yet previously unrecognized, role of the spontaneous curvature in determining vesicle responses under extreme osmotic stress. We utilize numerical experiments to construct phase diagrams of pore dynamics, which are consistent with the experimental observations, and we further discuss the impacts of compositional lipid properties. Our work not only advances a fundamental understanding of vesicle response in nonequilibrium environments, but also extends the possibility for precise design of vesicle systems regarding controlled release of therapeutic substances in biomedical applications.