Figure 1.

Principle of SOFI with oligonucleotide‐based exchangeable fluorophore labels. A) Labeling of cellular structures using oligonucleotide‐conjugated (docking strands) secondary antibodies and sequence‐complementary, fluorophore‐labeled oligonucleotides (imager strands). Transient and reversible binding of imager strands causes target‐specific intensity fluctuations. B) Image processing in SOFI via time‐trace analysis of stochastically fluctuating emitters. SOFI images are resolution and contrast enhanced and exhibit reduced unspecific background signals. C) Diffraction limited (i) and resolution‐enhanced 2^nd order SOFI image (ii) of a microtubule‐labeled U2‐OS cell using P1‐AbberiorStar635P as exchangeable imager strand (scale bar 10 μm).