Delayed release singlet oxygen sensitizers based on pyridone-appended porphyrins

Abstract

A new type of porphyrin photosensitizer capable of generating singlet oxygen upon irradiation, storing it through binding to pyridone subunits, followed by slow release at 20‐40 °C is reported. The timescale of singlet oxygen release can be varied depending on the pyridone group substitution pattern, forming endoperoxides of different stability. Modified tetra‐ and octasubstituted pyridone‐porphyrins showed solubility in water, allowing for straightforward delivery into cells. The effect of delayed singlet oxygen formation due to endoperoxide decomposition was demonstrated on cancer cells in vitro.