Enhanced one- and two-photon excitation emission of a porphyrin photosensitizer by FRET from a conjugated polyelectrolyte

Abstract

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 onephoton excitation Forster resonance energy transfer (FRET), and an enhancement factor of 30-fold for two-photon excitation FRIT were obtained. This electrostatic assembly can be easily modified in the future to construct DMA- or proteinprogrammed enhancement of porphyrin emission, which will be of great interest in porphyrin-based applications. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.