Fig. 4. DNA origami based nanocavities. (a) Basic principle: a “long” ss-DNA sequence (Scaffold) is folded with the help of hundreds of “short” ss-DNA sequences into the predesigned shape. MNPs, previously functionalized with DNA, can be incorporated through DNA hybridization. (b) Bowtie antennas self-assembled onto DNA origami structures fabricated based on two rectangular DNA origami structures. A single Cy5 Raman active molecule is incorporated at the bowtie hotspot. (c) Corresponding TEM image (scale bar 50 nm) and (d) Raman spectra of an individual bowtie with a single Cy5 (red) and a bulk solution of Cy5 (black). (b)–(d) have been reproduced from ref. 76 with permission from Wiley, copyright 2018.