Activatable Photosensitizers for Imaging and Therapy

Photodynamic therapy (PDT) is a minimally invasive treatment that destroys target cells in the presence of oxygen when light irradiates a photosensitizer, generating highly reactive singlet oxygen. PDT has low systemic toxicity, it can emission of fluorescence. Photosensitizers are not restricted solely to therapeutic generation of singlet oxygen. The fluorescence spectra of a photosensitizer may differentiate normal and malignant regions, acting as an image-guidance tool. The intrinsic fluorescence of activatable photosensitizers not only allows for convenient estimation of singlet oxygen production status but also permits useful in vivo imaging. Nucleic acids have demonstrated utility for regulating the activation of photosensitizers. Conversions of fluorescence imaging probes to activatable photosensitizers can occur from a wide pool of activatable fluorophores.