Figure 1. Illustration of the procedure for determination of absolute cross sections for DNA strand breakage using the DNA origami based DNA nanoarrays.

(a) Scheme showing protruding DNA strands of different nucleotide sequence. On the right-hand side the sequences are shown, which are investigated here. Green sequences are placed onto the center of the trapezoids, and black sequences are placed onto the side positions of the trapezoids. (b) After SAv incubation the two positions can be distinguished in AFM images. On the left a typical AFM image of non-irradiated DNA origami samples carrying TT(GTG)₃TT and TT(GBrUG)₃TT oligonucleotides is shown. On the right, a typical AFM image after irradiation with 18 eV electrons is shown. The number of specifically bound SAv is reduced due to strand breaks in the protruding sequences.