Toxicity of pristine versus functionalized fullerenes: mechanisms of cell damage and the role of oxidative stress

Abstract

The fullerene C(60), due to the physicochemical properties of its spherical cage-like molecule build exclusively from carbon atoms, is able to both scavenge and generate reactive oxygen species. While this unique dual property could be exploited in biomedicine, the low water solubility of C(60) hampers the investigation of its behavior in biological systems. The C(60) can be brought into water by solvent extraction, by complexation with surfactants/polymers, or by long-term stirring, yielding pristine (unmodified) fullerene suspensions. On the other hand, a modification of the C(60) core by the attachment of various functional groups results in the formation of water-soluble fullerene derivatives. Assessment of toxicity associated with C(60) preparations is of pivotal importance for their biomedical application as cytoprotective (antioxidant), cytotoxic (anticancer), or drug delivery agents. Moreover, the widespread industrial utilization of fullerenes may also have implications for human health. However, the alterations in physicochemical properties imposed by the utilization of different methods for C(60) solubilization profoundly influence toxicological effects of fullerene preparations, thus making the analysis of their potential therapeutic and environmental toxicity difficult. This review provides a comprehensive evaluation of the in vitro and in vivo toxicity of fullerenes, focusing on the comparison between pristine and derivatized C(60) preparations and the mechanisms of their toxicity to mammalian cells and tissues.

Comprehensive evaluation of carboxylated nanodiamond as a topical drug delivery system

“…46 In addition, chemically functionalized CNPs have shown reduced tissue accumulation and cytotoxicity compared with pristine CNPs. 47,48 These physicochemical properties of ND-COOH may contribute to low cytotoxicity during the incubation.…”

Mechanistic Understanding of Toxicity from Nanocatalysts

“…When intratracheal instillation and inhalation were used, neither pristine nor functionalized fullerenes caused significant histopathologic abnormalities, with the exception of a slight and transient lung inflammation [52,53,54,55]. In contrast, using intraperitoneal or intravenous administration, both pristine and derivatized C60 nanoparticles showed toxic effects at high doses (>500 mg/kg) and antioxidant tissue-protective effects at lower doses [56]. However, no significant toxicity was observed when animals were exposed to C60 nanoparticles through the oral, dermal, or ocular route [57,58,59].…”

Nanotoxicology: Contemporary Issues and Future Directions

“…Assessment of toxicity associated with C60 fullerene preparations is of pivotal importance for their biomedical application as cytoprotective (antioxidant), cytotoxic anticancer, theragnostic or drug delivery agents. Moreover, the widespread industrial utilization of fullerenes may also have implications for human health [ 205 ]. In another study, adult zebrafi sh exposed to the 30 mg/kg dose fullerene for 24 h have shown enhanced Acetylcholine esterase (AChE) activity and increased oxidative stress (increased lipid peroxidation levels) in brain, suggesting the possibility of fullerene nanoparticles crossing the bloodbrain barrier and reaching the brain and causing toxicity [ 206 ].…”