Biological applications of hydrophilic C60 derivatives (hC60s)− a structural perspective

• Hydrophilic C60 derivatives serve as ROS producer, radical scavenger, O2 uptake inhibitor, HIV inhibitor and vectors for DNA or drugs.
• Although each hydrophilic C60 derivative has the potential to be both, they show a preference. The propensity is dependent on C60s structure.
• High 1O2 quantum yield means low aggregation. C60s with aggregates scarcely generate 1O2, but O2
• −.
• The typical reactions to get covalent C60s are oxidation, Bingel reaction, Prato reaction, Diel–Alder reaction and radical polymerization.

Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C60 derivatives (hC60s). hC60s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C60 suspension, the aqueous solution of hC60s is easier to handle in vivo. hC60s are diverse and could be placed into two general categories: covalently modified C60 derivatives and pristine C60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C60(OH)n, C60 with carboxylic acid, C60 with quaternary ammonium salts, C60 with peptide, C60 containing sugar, C60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C60 delivered by liposomes, functionalized C60-polymer and pristine C60 solubilized by polymer. Each hC60 shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC60s structures. For example, major application of C60(OH)n is radical scavenger, while pristine C60/γ-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC60s with O2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC60s according to the structures.

Figure optionsDownload as PowerPoint slide