Title: Antimicrobial photodynamic therapy with decacationic monoadducts and bisadducts of [70]fullerene: in vitro and in vivo studies

Authors: Liyi Huang, Min Wang, Tianhong Dai, Felipe F Sperandio, Ying-Ying Huang, Yi Xuan, Long Y Chiang & Michael R Hamblin

Abstract:

Background: Antimicrobial photodynamic therapy uses photosensitizers designed to bind to microorganisms and generate reactive oxygen species when illuminated with visible light. Materials & method: We synthesized a highly water-soluble [70]fullerene monoadduct, C₇₀[>M(C₃N₆⁺C₃)₂]-(I^–)₁₀ (LC17), and bisadduct, C₇₀[>M(C₃N₆⁺C₃)₂][>M(C₃N₆C₃)₂] (LC18), both with a well-defined decacationic quaternary ammonium iodide moiety with ten positive charges per C₇₀ to give water solubility and bacterial binding. We determined the antimicrobial effects against human pathogens, Gram-positive (Staphylococcus aureus) and Gram-negative species (Escherichia coli and Acinetobacter baumannii) when activated by UVA or white light. Results: White light was more effective with LC17, while UVA light was more effective with LC18. Both compounds were effective in a mouse model of Gram-negative third-degree burn infections determined by bioluminescence imaging. Discussion & conclusion: We propose that the attachment of an additional deca(tertiary-ethylenylamino)malonate arm to C₇₀ allowed the moiety to act as a potent electron donor and increased the generation yield of hydroxyl radicals under UVA illumination.

Direct link: http://www.futuremedicine.com/doi/abs/10.2217/nnm.13.22