Fig. 4: Effect of surface hydrophilicity and microwell size on crystal growth.

a Schematic and optical images of DNA frame superlattice grown on piranha solution freshly treated silicon wafers or aged silicon wafers (exposed to air for days after piranha solution etching) with 100 µm and 20 µm microwell arrays (In both cases, DNA frame concentration was 150 nM). The top-left images are water contact angle measurements of the silicon wafers. The microwells were outlined with green dash lines. b Histogram of crystal sizes (N = 151–173) and the percentages of surface coverage of crystals over microwells (N = 39–99) on freshly etched vs aged silicon wafers. c Representation of crystals grown in a microwell array with 20 µm size and 100 µm spacing on freshly etched surfaces. d Representation of crystals grown in a microwell array with 10 µm microwell and 100 µm spacing on freshly etched surfaces.