  DNA origami is a novel self-assembly technique allowing one to form various
2D shapes and position matter with nanometer accuracy. It has been used to
coordinate placement of nanoscale objects, both organic and inorganic; to make
molecular motors and walkers; and to create optically active nanostructures.
Here we use DNA origami templates to engineer Surfaced Enhanced Raman
Scattering (SERS) substrates. Specifically, gold nanoparticles were selectively
attached to the corners of rectangular origami and subsequently enlarged via
solution-based metal deposition. The resulting assemblies were designed to form
"hot spots" of enhanced electromagnetic field between the nanoparticles. We
observed a significant enhancement of the Raman signal from molecules
covalently attached to the assemblies, as compared to control nanoparticle
samples which lack inter-particle hot spots. Our method opens up the prospects
of using DNA origami to rationally engineer and assemble plasmonic structures
for molecular spectroscopy.
