The photodynamic activity of a carrier-sensitizer system consisting of heterotopic colloidal nanoparticles (diameter 100-1000 nm) of a cationic amphiphilic
cyclodextrin, heptakis(2-omega-amino-O-oligo(ethylene oxide)-6-hexylthio)-beta-CD (SC6CDNH2) encapsulating the anionic 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphyrin (
TPPS) is investigated by an interdisciplinary approach involving the combination of time-resolved absorption and emission techniques with in vitro studies on cultured tumor cells. In a range of
TPPS:SC6CDNH2 molar ratios between 1:10 and 1:50 these nanoparticles preserve the photodynamic properties of the entrapped photoactive agent. In fact, the triplet state of
TPPS is efficiently populated, very long-lived and, as a consequence, able to produce
singlet oxygen (the essential species for the photodynamic action) with quantum yield comparable to the free
TPPS. Photodynamic efficacy of the carrier/sensitizer system is proven by in vitro studies on
tumor Hela cells treated with
TPPS:SC6CDNH2 at different molar ratio, showing significant cells death upon illumination with visible light.