ABSTRACT
We designed caging-group-free photoactivatable live-cell permeant dyes with red fluorescence emission and ∼100 nm Stokes shifts based on a 1-vinyl-10-silaxanthone imine core structure. The proposed fluorophores undergo byproduct-free one- and two-photon activation, are suitable for multicolor fluorescence microscopy in fixed and living cells and are compatible with super-resolution techniques such as STED (stimulated emission depletion) and PALM (photoactivated localization microscopy). Use of photoactivatable labels for strain-promoted azide-alkyne cycloaddition and self-labeling protein tags (HaloTag, SNAP-tag), and duplexing of imaging channel with another large Stokes shift dye have been demonstrated.
Competing Interest Statement
R.L., M.L.B. and A.N.B. are co-inventors of a patent application covering the photoactivatable dyes of this work, filed by the Max Planck Society. S.W.H. owns shares of Abberior GmbH and Abberior Instruments GmbH, whose dyes and STED microscope, respectively, have been used in this study. The remaining authors declare no competing interests.