3D superresolution microscopy by supercritical angle detection.

We present a fundamentally new approach to 3D superresolution microscopy based on the principle of surface-generated fluorescence. This near-field fluorescence is strongly dependent on the distance of fluorophores from the coverslip and can therefore be used to estimate their axial positions. We established a robust and simple implementation of supercritical angle fluorescence detection for single-molecule localization microscopy, calibrated it using fluorescent bead samples, validated the method with DNA origami tetrahedra, and present proof-of-principle data on biological samples.