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

ABSTRACT 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.