Protoporphyrin IX-gold nanoparticle conjugates as an efficient photosensitizer in cervical cancer therapy

Protoporphyrin IX (PpIX) conjugated gold nanoparticle (GNP) was synthesized, characterized, and used for the delivery of a hydrophobic photosensitizer to a cervical cancer cell line. The GNP conjugates have an average diameter of 7 nm. The conjugated GNPs were made by a single coupling reaction. Protoporphyrin absorbs radiation at 630 nm and catalytically produces the reactive oxygen species in high efficiency. These properties indicate that PpIX GNP conjugates could be used as a photosensitizer in photodynamic therapy (PDT) through the formulation of singlet oxygen. The conjugates were tested on Hela cells. PDT efficacy of the system was evaluated with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The effect of photon-induced toxicity was assessed by comparing it with control experiments. Our findings suggest that the PpIX-GNP conjugate is an excellent carrier for the delivery of surface bound hydrophobic protoporphyrin molecule into the cell which makes PpIX GNP conjugates potential candidates for PDT. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.