Figure 1.

Incorporation of arylazopyrazole (AAP) moieties into ssDNA allows for photoswitchable droplet formation

(A) AAP is able to undergo trans-to-cis isomerization under UV irradiation and reverts to its trans isomer upon irradiation of green light. AAP was incorporated into two positions in the native ODN sequence to give the modified AAP-ODN sequence. The structure of the positively charged AAP monomer, AAP-TAB, is as given.

(B) Microscopy images and droplet counts of mixtures of the various DNA sequences (1.85 mM phosphate) with pLys (2.5 mM amine) (scale bar: 10 μm). Although ODN and ODN + AAP-TAB exhibited limited droplet formation, only AAP-ODN showed significant photoswitching ability. Error bars represent standard deviation for three independent experiments. Irradiation was conducted in situ and the same field of view was maintained within each experiment.

(C) Droplets formed from AAP-ODN and pLys mixtures exhibited fusion and wetting behaviors which are typical of liquid droplets (scale bar: 20 μm; scale bar for zoomed inset: 10 μm).

See also Figure S1.