Enhanced One- and Two-Photon Excitation Emission of a Porphyrin Photosensitizes by FRET from a Conjugated Polyelectrolyte

Porphyrin-based systems are widely used as photosensitizers for photodynamic therapy, photocatalysis, and drug release. Strategies to enhance one- or two-photon excitation emission of porphyrin sensitizers have been of great interest and significance. Here we report an electrostatic assembly, which comprises a cationic conjugated polyelectrolyte, PFP, and a negatively charged hematoporphyrin (HP). An enhancement of over 9-fold in the HP emission intensity for one-photon excitation Forster resonance energy transfer (FRET), and an enhancement factor of 30-fold for two-photon excitation FRET were obtained. This electrostatic assembly can be easily modified in the future to construct DNA- or protein-programmed enhancement of porphyrin emission, which will be of great interest in porphyrin-based applications.