Figure 3: Super-resolution imaging with Oligopaints and DNA-PAINT.

(a) Labelling scheme using Oligopaint probes carrying an ATTO 488 dye and a 9-base docking site that is complementary to imager strands labelled with ATTO 655. (b) Trace of Intensity versus time showing the transient binding of imager strands and docking strands or ‘blinks’. (c,d) Diffraction-limited images obtained with ATTO 488 (left) and DNA-PAINT super-resolution images obtained with ATTO 655-labelled imager strands at 5 nM (right) of Oligopaint probe sets labelled with ATTO 488 and targeting 174 kb (c) and 5 kb (d) of the mouse hoxB locus in MEFs. To the right of the images are cross-sectional (dotted lines in DNA-PAINT images i–ix) histograms displaying the normalized number of photons detected (normalized counts) versus transverse position for each region. Structural features are inferred from these transverses with one-dimensional Gaussian fits, with FWHMs indicated above each graph. Imaging: 15,000 frames at 10 Hz rate. Super-resolution images are presented as heat maps of single-mole localization density: black (fewest) -> red -> yellow -> white (most).