Li, MenglinBrinkmann, MartinPagonabarraga Mora, IgnacioSeeman, RalfFleury, Jean-Baptiste2020-01-282020-01-282018-03-03https://hdl.handle.net/2445/148842Self-propelled droplets capable of transporting cargo to specific target locations are desired tools for many future applications. Here we propose a class of active droplets with programmable delivery time that are attracted or repelled by certain obstacle geometries. These droplets consist of a water/ethanol mixture and are dispersed in an oil/surfactant solution. Owing to a mass exchange between fluid phases during self-propulsion, the initially homogeneous droplets spontaneously de-mix and evolve into characteristic Janus droplets. Cargo molecules, like DNA, can be separated into the trailing ethanol-rich droplet and are carried to their target location 'like in a backpack'. The delayed onset of phase separation provides a handle to control the time frame of delivery, while long-ranged hydrodynamic interactions and short-ranged wetting forces are exploited to achieve the desired spatial specificity with respect to obstacle geometry and surface chemistry.8 p.application/pdfengcc-by (c) Li, Menglin et al., 2018http://creativecommons.org/licenses/by/3.0/esTransport biològicMolèculesMicrofluídicaFísica de partículesBiological transportMoleculesMicrofluidicsParticle physicsinfo:eu-repo/semantics/article6946502020-01-28info:eu-repo/semantics/openAccess