Wash-Free Multi-Target Super-Resolution Microscopy With Photocaged DNA Labels

Nina Kaltenschnee, Marina S. Dietz, Laurell F. Kessler, Yunqing Li, Janik Kaufmann, Alexander Heckel, Mike Heilemann

Angew. Chem. Int. Ed. 2026, 65, e26137
DOI: 10.1002/anie.202526137

Super-resolution microscopy with DNA-fluorophore labels is primed for multi-target imaging of cell biological samples. However, direct interaction with the sample is required to exchange or add DNA-fluorophore labels in each imaging round, which can impair the accuracy of the imaging data at the nanometer scale. To bypass this requirement, we introduce PhotoPAINT, a wash-free method that employs DNA oligonucleotides equipped with photocaging groups. Irradiation with light removes these photo-modulatable groups and changes the hybridization properties of DNA labels, enabling light-modulated targeting. We demonstrate this concept by imaging various cellular targets with confocal microscopy, single-molecule localization microscopy (SMLM), and stimulated emission depletion (STED) microscopy.