biostudies-literatureUnknown5(1)Shirt-Ediss BArtificial protocellular compartments and lipid vesicles have been used as model systems to understand the origins and requirements for early cells, as well as to design encapsulated reactors for biotechnology. One prominent feature of vesicles is the semi-permeable nature of their membranes, able to support passive diffusion of individual solute species into/out of the compartment, in addition to an osmotic water flow in the opposite direction to the net solute concentration gradient. Crucially, this water flow affects the internal aqueous volume of the vesicle in response to osmotic imbalances, in particular those created by ongoing reactions within the system. In this theoretical study, we pay attention to this often overlooked aspect and show, via the use of a simple semi-spatial vesicLife (Basel, Switzerland)181-211https://www.ebi.ac.uk/biostudies/studies/S-EPMC4390847biostudies-literatureEmergent chemical behavior in variable-volume protocells.PMC4390847Sole RVShirt-Ediss BRuiz-Mirazo KfalseEmergent chemical behavior in variable-volume protocells.Artificial protocellular compartments and lipid vesicles have been used as model systems to understand the origins and requirements for early cells, as well as to design encapsulated reactors for biotechnology. One prominent feature of vesicles is the semi-permeable nature of their membranes, able to support passive diffusion of individual solute species into/out of the compartment, in addition to an osmotic water flow in the opposite direction to the net solute concentration gradient. Crucially, this water flow affects the internal aqueous volume of the vesicle in response to osmotic imbalances, in particular those created by ongoing reactions within the system. In this theoretical study, we pay attention to this often overlooked aspect and show, via the use of a simple semi-spatial vesic2015-01-01T00:00:00Z2015 Jan2026-05-07T15:33:04.443Z2019-03-27T01:49:39ZS-EPMC43908472559057010.3390/life5010181