Soft Matter Based Nanofluidic Platform for Highly Parallel Mixing of Sub-Attoliter Total Volumes

Small unilamellar lipid vesicles (SUVs) arrayed at solid supports are useful as nanoscopic test tubes for microscopy-based experiments with few or single molecules(1). Encapsulation in SUVs enables spatial confinement of biomolecules at a glass coverslip while retaining them free in solution and in a native-like environment. Manipulating and mixing the content of individual SUVs has, however, proven challenging due to their nanoscopic dimensions. We demonstrate a fluidic platform that allows triggering highly parallelized mixing of reagents loaded in individual SUVs with self-enclosed volumes as small as 10−19 l(2). We encapsulated one set of reactants in vesicles immobilized at a glass surface and triggered fusion of these stationary nanoreactors with diffusing vesicles of opposite charge that carried a complementary set of reactants. Productive and leakage-free mixing was achieved on ∼85% of the ∼106 cm−2 surface-tethered vesicles with up to 3-4 consecutive injections per reactor. Development of ultra-small-volume fluidic platforms will enable novel ways to implement simultaneous screening of biochemical properties, molecular function or confined reactions over millions of samples while consuming total reagent volumes of few picoliters.References:(1) Christensen and Stamou,Soft Matter, 2007.(2) Christensen et al.,Nature Nanotechnology, 2011.View Large Image | View Hi-Res Image | Download PowerPoint Slide