De Novo Emergence of Minimal Protocellular Compartments

It is widely argued that compartmentalization, metabolism (catalytic, or otherwise) and heredity (reproduction with scope for variation) are key features that contrast living systems from the non-living. Here, using chemistries comprising only four small abiotic molecules, kept out of equilibrium by exposure to light, we demonstrate the spontaneous emergence of spherical compartments, characterized by a lumen separated from the exterior by a material barrier. Single compartments were found to exhibit characteristic growth dynamics --- the volume grows linearly in steady-state, indicating either a steady material flux or synthesis, underlying the growth. Further, at the population level the total compartment mass also increases super-linearly. This growth is concomitant with an increase in bulk proton and heat production, indicating ongoing chemical reactions associated with the compartment formation. Mass spectrometric analysis revealed that these compartments act as reaction crucibles, leading to the complexification of the initial molecular species, giving rise to significantly larger (bio-)molecules over time. Altogether, our findings raise the intriguing possibility of the spontaneous emergence of de novo protocells exhibiting growth and primitive metabolism from simple abiotic chemical mixture.