Fig. 3: pH-sensitive FRET and peptide quantification.
From: A DNA robotic switch with regulated autonomous display of cytotoxic ligand nanopatterns
a, The principle of using FRET to verify the pH-dependent formation of the tsDNA inside the DNA origami. When a tsDNA forms, the donor chromophore (Cy3) and acceptor chromophore (Cy5) get in proximity, showing FRET. The sequence of the tsDNA is indicated to the right. b, Changes of normalized (to FRET efficiency under pH 7.4) FRET efficiency ratio in buffers with different pH (n = 3 independent measurements). c, With an excitation of 520 nm, the emission spectrum of the origami samples under pH 7.4 or 6.5. d, Normalized (to FRET efficiency under pH 7.4) FRET efficiency ratio when we consecutively exchanged the origami samples between buffer with pH 7.4 and 6.5 (n = 2 independent measurements). e, Illustration of how we quantify peptides in origami. After loading the ssDNA–peptide conjugate into the origami, the peptide was detected using Cy5-labelled oligo that targets the TFO of the conjugate. f, Peptide quantification of origami structures with different numbers of mini-scaffold with the principle indicated in e (n = 3 independent measurements). RFU, relative fluorescence units. Data are presented as mean ± s.d.
