title: Photoinduced electron-transfer mechanisms for radical-enhanced photodynamic therapy mediated by water-soluble decacationic C₇₀ and C₈₄O₂ Fullerene Derivatives.
abstract: Fullerenes are promising candidates for photodynamic therapy (PDT). Thus, C₇₀ and novel C₈₄O₂ fullerenes were functionalized with and without an additional deca-tertiary ethyleneamino-chain as an electron source, giving rise to two distinct pairs of photosensitizers, the monoadducts LC-17, LC-19 and the bisadducts LC18 and LC-20 to perform PDT in HeLa cells with UVA, blue, green, white and red light. Shorter wavelengths gave more phototoxicity with LC-20 while LC-19 was better at longer wavelengths; the ratio between killing obtained with LC-19 and LC-20 showed an almost perfect linear correlation (R = 0.975) with wavelength. The incorporation of a deca-tertiary amine chain in the C₈₄O₂ fullerene gave more PDT killing when excited with shorter wavelengths or in the presence of low ascorbate concentration through higher generation of hydroxyl radicals. Photoactivated C₈₄O₂ fullerenes induced apoptosis of HeLa cancer cells, together with mitochondrial and lysosomal damage demonstrated by acridine orange and rhodamine 123 fluorescent probes.
  
  
  BACKGROUND
  Photoactivated C₇₀ and C₈₄O₂ fullerenes were demonstrated to induce apoptosis of HeLa cancer cells, together with mitochondrial and lysosomal damage, as a function of wavelength. The study is paving the way to future clinical uses of these agents in photodynamic therapy.
authors.affiliation: Department of Oral Pathology, School of Dentistry, University of Sao Paulo, Sao Paulo, SP 05508-000, Brazil.
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Sperandio
authors.forename: Sulbha K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Seaho
authors.initials: S
authors.lastname: Jeon
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Huang
authors.forename: Tianhong
authors.initials: T
authors.lastname: Dai
authors.forename: Suhasini
authors.initials: S
authors.lastname: Nayka
authors.forename: Suzana C O M
authors.initials: SC
authors.lastname: de Sousa
authors.forename: Long Y
authors.initials: LY
authors.lastname: Chiang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D004579:Electron Transport; D005609:Free Radicals; D037741:Fullerenes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D055668:Photochemical Processes; D010778:Photochemotherapy; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D005609:Free Radicals; D037741:Fullerenes; D014867:Water