title: The effect of ascorbic acid on the photophysical properties and photodynamic therapy activities of zinc phthalocyanine-single walled carbon nanotube conjugate on MCF-7 cancer cells.
abstract: Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π-π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Racheal O
authors.initials: RO
authors.lastname: Ogbodu
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa. Electronic address: t.nyokong@ru.ac.za.
authors.forename: Tebello
authors.initials: T
authors.lastname: Nyokong
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D006801:Humans; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D061986:MCF-7 Cells; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010778:Photochemotherapy; D055585:Physical Phenomena; D011789:Quantum Theory; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction; D017967:Zinc Compounds
chemical_list: D000975:Antioxidants; D007211:Indoles; D054833:Isoindoles; D037742:Nanotubes, Carbon; D009942:Organometallic Compounds; D011838:Radiation-Sensitizing Agents; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D001205:Ascorbic Acid
keywords: Ascorbic acid; Photodynamic therapy; Single walled carbon nanotubes; Singlet oxygen quantum yield; Zinc carboxy phenoxy phthalocyanine