Near IR excitation of heavy atom free Bodipy photosensitizers through the intermediacy of upconverting nanoparticles.

Orthogonal dimers of Bodipy were recently shown to be efficient generators of singlet oxygen. However, these dyes require green light for excitation, which would be very quickly attenuated inside the mammalian tissues. We now demonstrate that when these dyes are covalently attached to UCNPs, near IR irradiation results in very efficient generation of singlet oxygen.