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

Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C-60 derivatives (hC(60)s). hC(60)s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C-60 suspension, the aqueous solution of hC(60)s is easier to handle in vivo. hC(60)s are diverse and could be placed into two general categories: covalently modified C-60 derivatives and pristine C-60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C-60(OH)(n), C-60 with carboxylic acid, C-60 with quaternary ammonium salts, C-60 with peptide, C-60 containing sugar, C-60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C-60 delivered by liposomes, functionalized C-60-polymer and pristine C60 solubilized by polymer. Each hC(60) shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC(60)s structures. For example, major application of C-60(OH)(n) is radical scavenger, while pristine C-60/gamma-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC(60)s with O-2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC(60)s according to the structures. (C) 2016 Elsevier Masson SAS. All rights reserved.