Figure 3.

Synthesis of gold nanoparticles with constrictions using 3‐wall structures. Design schemes are shown on top and corresponding tSEM images at the bottom of each subfigure. a) Mold structure based on DNA double layers (indicated by the red arrows) compared to the 3‐wall structure based on a DNA triple layer (indicated by the green arrows). b) 3‐wall–mold–3‐wall trimer. AuNP seeds were loaded into the mold centers and onto the ends of each 3‐wall structure (center). Seeded gold growth provided rolling‐pin‐shaped gold particles (bottom). c) Mold–3‐wall–mold trimer. AuNP seeds were loaded into the mold centers and onto both ends of the 3‐wall structure (center). Seeded gold growth provided dumbbell‐shaped gold particles (bottom). d) Chains with an alternating mold–3‐wall pattern (center) supported the formation of gold nanowires with periodically changing diameter (bottom). The positions of the 3‐wall elements are indicated by green arrows. Occasional empty 3‐wall elements are marked by the blue arrows. The scale bars are 20 nm.