Photocytotoxicity of porphyrin@GO hybrids against cancer cells

Photodynamic therapy (PDT) is a minimally invasive medical technology which promotes cytotoxicity activity towards tumoral malignant cells.1 Porphyrins assume leading roles as photosensitizers for PDT, due to their remarkable light absorption characteristics, minimal dark toxicity and good ability to generate singlet oxygen.1 To improve their physiological solubility and selectivity, porphyrins have been functionalized with graphene oxide (GO).2 Throughout this research work, different tetracationic porphyrins were non-covalently conjugated to GO: i) the 5,10,15,20-tetrakis(1-methylpyridinium-4- yl)porphyrin (TMPyP), ii) ZnTMPyP and iii) a dibenzoporphyrin analogue of TMPyP (P1-C5). The formation of such hybrids was monitored through spectroscopic titrations, Raman mapping and electron microscopy.3 The photocytotoxicity of the nonimmobilized porphyrins, of GO and of hybrid systems on T24 human bladder cancer cells was evaluated through PDT assays under irradiation with blue (BL; 417 nm) or red light (RL; 630 nm).