Autonomic Behaviors in Lipase-Active Oil Droplets

Developing self-fueled micro-reactor droplets with programmable autonomic behaviors provides a step towards smart liquid dispersions comprising motile microscale objects. Herein, we prepare aqueous suspensions of lipase-coated oil globules comprising a mixture of a triglyceride substrate (tributyrin, 1,2,3-tributylglycerol) and a low-density oil (polydimethylsiloxane, PDMS) and describe a range of active behaviors based on controlled enzyme-mediated consumption of individual droplets under non-equilibrium conditions. Encapsulation of the lipase-coated lipid/PDMS droplets into a model protocell as energy-rich sub-compartments is demonstrated as an internalized mechanism for activating protocell buoyancy. Taken together, our results highlight opportunities for the regulation of autonomic behavior in enzyme-powered oil droplets and provide a new platform for increasing the functionality and energization of synthetic protocells.