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Pure Appl. Chem., 2011, Vol. 83, No. 9, pp. 1763-1779

Published online 2011-06-12

Desired properties of new phthalocyanines for photodynamic therapy

Tebello Nyokong

Department of Chemistry, Rhodes University, Grahamstown, South Africa

Abstract: The manuscript focuses on the properties of phthalocyanines (Pcs) that are required for them to be employed as photosensitizers in applications such as photodynamic therapy (PDT). High triplet-state quantum yields and lifetimes as well as high singlet-oxygen quantum yields are required for a good photosensitizer. In addition, absorption of the photosensitizer in the red region of the electromagnetic spectrum is also required, and this can be achieved by ring expansion, substitution with electron-donating ligands, and change of the central metal among others. Quantum dots (QDs) are efficient accumulators of light energy, and they can transfer this energy to molecules that possess a very efficient ability to generate singlet oxygen through a process called Förster resonance energy transfer (FRET). Thus, there is a decrease in the fluorescence quantum yield of the QDs when in the vicinity of Pcs. Triplet quantum yields of the Pcs increase in the presence of QDs.