Christensen, S.M. et al. Nat. Nanotechnol. advance online publication (30 October 2011).

High-throughput screening can benefit from miniaturization, requiring smaller amounts of reagents and allowing more complex assays to be performed. Christensen et al. describe a nanofluidics platform for handling and mixing sub-attoliter volumes of reactants, in a reproducible, parallelized manner. They make arrays of small unilamellar vesicles (SUVs) by extruding the SUVs through polycarbonate membrane pores and immobilizing the SUVs on functionalized glass surfaces. By functionalizing 'target' and 'cargo' SUV reactors with lipids of opposite charge, this platform allowed them to mix volumes as small as 1 × 10−19 liters. As a proof-of-principle demonstration, the researchers mixed SUVs containing the enzyme alkaline phosphatase with SUVs containing the substrate fluorescein diphosphate and observed the formation of the fluorescent produce fluorescein.