Fig. 1: Schematic of DNA tiles and nanotubes and different methods for encapsulating and assembling DNA nanotubes in water-in-oil droplets.

a DNA tiles composed of five unique ssDNA oligomers (shown in blue, red, yellow, green, and purple strands) that self-assemble into DNA nanotubes. Assembly occurs via hybridization of single-stranded complementary domains known as sticky-ends (marked as a, complementary to a′, and b complementary b′). Tiles are labeled with a fluorescent molecule, indicated here by the yellow star, for easy observation of DNA nanotubes under fluorescence microscopy. b DNA nanotubes can be pre-annealed from constituent oligomers in vitro before encapsulation in water-in-oil droplets. Representative fluorescence microscopy images of pre-annealed DNA nanotubes inside droplets using two different encapsulation protocols. c Nanotubes encapsulated via the shaken protocol at room temperature. Tile concentration is 500 nM. d Nanotubes encapsulated via the microfluidic protocol at room temperature. Tile concentration is 350 nM. e Constituent oligomers can be encapsulated inside the droplets and later annealed to form nanotubes. Multiple species of nanotubes can be simultaneously annealed in the droplets if the required strands are present in the initial encapsulated solution. f Representative fluorescence microscopy image of a single nanotube species annealed inside droplets (250 nM tile concentration) and then imaged at room temperature. g Example fluorescence image of two distinct species of DNA nanotubes annealed inside droplets (250 nM each tile), labeled with Cy3 dye (white) and Atto647N dye (red), respectively and then imaged at room temperature. Scale bars: 30 μm.