Nanoscale pipetting for controlled chemistry in small arrayed water droplets using a double-barrel pipet.

We present a new methodology which provides for the miniaturization of one of the most common tools in use in chemistry and biology laboratories today-the micropipet. We have used glass-fabricated double-barrel nanopipets to controllably produce arrayed water droplets with volumes as small as a few attoliters under an organic layer. We have addressed individual droplets and added controlled amounts of either additional volume or reagents from one of the barrels of the pipet. We demonstrate that this method can be used for miniaturized cell-free protein expression.