High-order super-resolution optical fluctuation imaging with ultrasmall polymer dots

Super-resolution optical fluctuation imaging (SOFI) rapidly generates super-resolution images by analyzing fluorescence intensity fluctuations. However, fluorophores for high-order SOFI applications are very rare. Here, we report ultrasmall semiconducting polymer dots (Pdots) to achieve high-order SOFI at single-particle and cellular levels. The ultrasmall Pdots exhibit an average diameter of ∼7 nm and superior photoblinking characteristics. The Pdot bioconjugates specifically labeled subcellular structures and demonstrated super-resolution imaging with a spatial resolution of ∼64 nm, which is ∼6 times enhancement compared to wide-field images. This study demonstrates the potential of the small-sized semiconductor Pdots for high-order SOFI in biomedical applications.