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International Journal of Photoenergy
Volume 2014 (2014), Article ID 793723, 7 pages
Research Article

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell Line In Vitro

1Department of Chemistry, Yonsei University, 50 Yonsero, Seodaemun-Gu, Seoul 120-749, Republic of Korea
2Department of Microbiology, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
3Department of Chemistry, Kangwon National University, Chuncheon 200-701, Republic of Korea
4Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, 211 Eonjuro, Gangnam-Gu, Seoul 135-720, Republic of Korea

Received 20 May 2014; Revised 24 July 2014; Accepted 24 July 2014; Published 10 August 2014

Academic Editor: Leonardo Palmisano

Copyright © 2014 Kang-Kyun Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Pheophorbide-a derivatives have been reported to be potential photosensitizers for photodynamic therapy (PDT). In this study, photophysics of pheophorbide-a derivatives (PaDs) were investigated along with their photodynamic tumoricidal effect in vitro. PaDs were modified by changing the coil length and/or making the hydroxyl group (–OH) substitutions. Their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. The photodynamic tumoricidal effect was evaluated in the mouse breast cancer cell line (EMT6). Lifetime and quantum yield of fluorescence and quantum yields of triplet state and singlet oxygen were studied to determine the dynamic energy flow. The coil length of the substituted alkyl group did not significantly affect the spectroscopic properties. However, the substitution with the hydroxyl group increased the quantum yields of the triplet state and the singlet oxygen due to the enhanced intersystem crossing. In order to check the application possibility as a photodynamic therapy agent, the PaDs with hydroxyl group were studied for the cellular affinity and the photodynamic tumoricidal effect of EMT6. The results showed that the cellular affinity and the photodynamic tumoricidal effect of PaDs with the hydroxyl group depended on the coil-length of the substituted alkyl group.