DNA Mold-Based Fabrication of Palladium Nanostructures

DNA origami molds allow a shape-controlled growth of metallic nanoparticles. So far, this approach is limited to gold and silver. Here, the fabrication of linear palladium nanostructures with controlled lengths and patterns is demonstrated. To obtain nucleation centers for a seeded growth, a synthesis procedure of palladium nanoparticles (PdNPs) using Bis(p-sulfonatophenyl)phenylphosphine (BSPP) both as reductant and stabilizer is developed to establish an efficient functionalization protocol of the particles with single-stranded DNA. Attaching the functionalized particles to complementary DNA strands inside DNA mold cavities supports subsequently a highly specific seeded palladium deposition. This provides rod-like PdNPs with diameters of 20-35 nm of grainy morphology. Using an annealing procedure and a post-reduction step with hydrogen, homogeneous palladium nanostructures can be obtained. With the adaptation of the procedure to palladium the capabilities of the mold-based tool-box are expanded. In the future, this may allow a facile adaptation of the mold approach to less noble metals including magnetic materials such as Ni and Co.

Automated summary

DNA origami molds enable controlled growth of metallic nanoparticles, but it is currently limited to gold and silver. This study demonstrates the fabrication of linear palladium nanostructures with controlled lengths and patterns. By developing a synthesis procedure of palladium nanoparticles using BSPP as a reductant and stabilizer, an efficient functionalization protocol with single-stranded DNA is established. Attaching functionalized particles to complementary DNA strands inside DNA molds allows specific seeded palladium deposition, resulting in rod-like palladium nanoparticles with grainy morphology.