Photodynamic therapy with fullerenes

Abstract

Fullerenes are a class of closed-cage nanomaterials made exclusively from carbon atoms. A great deal of attention has been focused on developing medical uses of these unique molecules especially when they are derivatized with functional groups to make them soluble and therefore able to interact with biological systems. Due to their extended π-conjugation they absorb visible light, have a high triplet yield and can generate reactive oxygen species upon illumination, suggesting a possible role of fullerenes in photodynamic therapy. Depending on the functional groups introduced into the molecule, fullerenes can effectively photoinactivate either or both pathogenic microbial cells and malignant cancer cells. The mechanism appears to involve superoxide anion as well as singlet oxygen, and under the right conditions fullerenes may have advantages over clinically applied photosensitizers for mediating photodynamic therapy of certain diseases.

Fullerol modification ferrihydrite for the degradation of acid red 18 under simulated sunlight irradiation

“…This phenomenon further implied that the presence of PHF could enhance the photo-Fenton catalytic activity of Fh. The excited state PHF could not only generate 1 O 2 [4][5][6][7], but also could transfer electrons to the Fe 3+ on Fh [9,31], which can then further promote the decomposition of H 2 O 2 into highly oxidative • OH. Hence, the high removal efficiency of AR18 by PHF/Fh might be attributed to the reaction of AR18 with small amounts of 1 O 2 photosensitized by PHF, or to the increased amounts of • OH produced by the synergetic effect of PHF and Fh.…”

“…8). The first one might originate from the excited state PHF, which can efficiently sensitize the ground state triplet oxygen to generate 1 O 2 [4][5][6][7]. Another one might be attributed to the synergetic effect between PHF and Fh, and the excited state PHF could reduce and transfer electrons to the Fe 3+ on Fh due to E 0 (C 60 + / 1 C 60 *) = 0.1 V vs. NHE < E 0 (Fe 3+ /Fe 2+ ) = 0.77 V vs. NHE [9,31].…”

“…The excited state C 60 and its derivatives such as fullerol (polyhydroxyfullerene, PHF) are able to generate 1 O 2 , a selective oxidant useful in applications such as photocatalysis for wastewater treatment, through photosensitization [4][5][6][7]. On the other hand, C 60 and PHF in the electron-transfer processes can efficiently arouse a rapid photoinduced charge separation and a relatively slow charge recombination [8]; and thus they have been frequently studied as electron acceptors or electron carriers for enhancing charge separation in many semiconductor photocatalytic systems, such as PHF/TiO 2 [9,10], CdS-C 60 /TiO 2 [11], C 60 /ZnO [12], and C 60 /Bi 2 WO 6 [13].…”

New Approaches to Photodynamic Therapy from Types I, II and III to Type IV Using One or More Photons

“…However, much research activity has been devoted to demonstrating PSs based on other molecular structures for both pre-clinical and clinical studies, e.g. fullerenes [17,43,[59][60][61].…”

Effective Polarizability Models

“…6 The impact of a cavity around the particles is large compared to the typically studied situations where the particles are considered without an environment.…”