Abstract

The growth of lipid membranes plays a crucial role in many cellular processes, including the formation and spatial organization of vital cellular organelles. These processes often involve a delicate interplay of material exchange, shape dynamics, in-plane viscous flow, and apparent changes in material properties, and understanding how they are controlled remains an ongoing challenge. As a step in this direction, we consider a minimal fluid vesicle model in which growth is driven by coupling to a material reservoir. In simulations, we find that sufficiently strong nonequilibrium driving produces a striking morphological instability marked by out-of-plane buckling and dramatic changes in growth rate. We then discuss how the driving strength is quantitatively related to the growth rate, size fluctuations, and effective surface tension, using a combination of approaches from linear irreversible and stochastic thermodynamics. Our results suggest a multifaceted approach for understanding and constraining the effects of active driving forces on the mechanics and morphology of biological matter.