Abstract
Recent advances in localization-based super-resolution microscopy have enabled researchers to visualize single molecular features down to individual molecular components (~5 nm), but do not yet allow manipulation of single-molecule targets in a user-prescribed, context-dependent manner. Here we report an 'Action-PAINT' (PAINT, point accumulation for imaging in nanoscale topography) strategy for super-resolution labelling upon visualization on single molecules. This approach monitors and localizes DNA binding events in real time with DNA-PAINT, and upon visualization of binding to a desired location, photo-crosslinks the DNA to affix the molecular label. We showed the efficiency of 3-cyanovinylcarbazole nucleoside photo-inducible crosslinking on single molecular targets and developed a software package for real-time super-resolution imaging and crosslinking control. We then benchmarked our super-resolution labelling method on synthetic DNA nanostructures and demonstrated targeted multipoint labelling on various complex patterns with 30 nm selectivity. Finally, we performed targeted in situ labelling on fixed microtubule samples with a 40 nm target size and custom-controlled, subdiffraction spacing.