Identifying STEDable BF2-Azadipyrromethene Fluorophores

BF2-azadipyrromethenes are highly versatile fluorophores used for cellular and in vivo imaging in the near-infrared and far-red regions of the spectrum. As of yet, their use in conjunction with super-resolution imaging methodologies has not been explored. In this report, a series of structurally related BF2-azadipyrromethenes has been examined for their suitability for use with stimulated emission depletion (STED) nanoscopy. The potential for STED imaging was initially evaluated using aqueous solutions of fluorophores as an effective predictor of fluorophore suitability. For live cell STED imaging in both 2D and 3D, several far-red emitting BF2-azadipyrromethenes were successfully employed. Image resolution below the diffraction limit of a confocal microscope was demonstrated through measurement of distinct intracellular features including the nuclear membrane, nuclear lamina invaginations, the endoplasmic reticulum, and vacuoles. As the STED ability of BF2-azadipyrromethene fluorophores has now been established, their use with this super-resolution method may be expected to increase in the future.

Automated summary

BF2-azadipyrromethenes are versatile fluorophores used for cellular and in vivo imaging in the near-infrared and far-red regions. However, their usage with super-resolution imaging techniques like STED nanoscopy has not been explored. In this study, a series of structurally related BF2-azadipyrromethenes were evaluated for their suitability in STED imaging. The study demonstrated successful live cell STED imaging using far-red emitting BF2-azadipyrromethenes, achieving resolution below the diffraction limit.