Self-Assembled Plasmonic DNA Origami Nanoantennas for Diagnostics Applications with Low-Tech Devices

The DNA origami technique provides an unprecedented method to create multiple copies of well-defined self-assembled nanostructures.1 Methods of modern chemistry allow to functionalize DNA with molecules and functional groups of interest. Exploiting these features we designed a pillar-shaped 3D DNA origami nanostructure functionalized with biotins for the surface immobilization and docking strands allowing to precisely position plasmonic nanoparticles. Upon illumination with freely propagating light, the local electric field between nanoparticles increases and a dye placed in the plasmonic hotspot exhibits a fluorescence gain of several orders of magnitude.2 In our present work, we modified a hotspot region with molecular recognition units (molecular beacon3 or sandwich assay) to detect an enhanced signal only in the presence of a specific nucleic acid target (Figure 1).