The Differential Cytotoxicity of Water-Soluble Fullerenes

TLDR

The study aims to develop strategies that enhance fullerene toxicity for therapeutic or bactericidal applications while mitigating unintended biological effects. Fullerenes generate superoxide anions in aqueous environments, which are proposed to cause membrane damage leading to cell death. Cytotoxicity of water‑soluble fullerenes varies dramatically with surface derivatization, with less derivatized aggregated C60 being far more toxic; oxidative membrane damage and superoxide generation are implicated.

Abstract

We show that the cytotoxicity of water-soluble fullerene species is a sensitive function of surface derivatization; in two different human cell lines, the lethal dose of fullerene changed over 7 orders of magnitude with relatively minor alterations in fullerene structure. In particular, an aggregated form of C60, the least derivatized of the four materials, was substantially more toxic than highly soluble derivatives such as C3, Na+2-3[C60O7-9(OH)12-15](2-3)-, and C60(OH)24. Oxidative damage to the cell membranes was observed in all cases where fullerene exposure led to cell death. We show that under ambient conditions in water fullerenes can generate superoxide anions and postulate that these oxygen radicals are responsible for membrane damage and subsequent cell death. This work demonstrates both a strategy for enhancing the toxicity of fullerenes for certain applications such as cancer therapeutics or bactericides, as well as a remediation for the possible unwarranted biological effects of pristine fullerenes.