Enhanced radical scavenging activity of polyhydroxylated C60 functionalized cellulose nanocrystals

A first demonstration of conjugated polyhydroxylated fullerene (C-60(OH)(30)) on the surface of cellulose nanocrystals (CNC)s is reported. These nanohybrids display favourable antioxidant performance and are an attractive alternative to derivatized fullerene nanocages reported previously. UV-Vis measurements indicated that the C-60(OH)(30)-CNC system scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals to a greater degree than C-60(OH)(30) alone, due to the nucleation of C-60(OH)(30) on the surface of CNC and high colloidal stability of the engineered nanohybrid. A mechanism for the 2-stage process of the radical reaction with C-60(OH)(30)-CNC is proposed, and modelled by pseudo-first order kinetics. Successful grafting of C-60(OH)(30) on CNC was confirmed by FTIR, while TEM revealed the morphology of the system with a grafting degree of 20.8 % C-60(OH)(30). Zeta potential measurements of C-60(OH)(30)-CNC in aqueous solution showed a high stability in the pH range 4.0-8.0, indicating functionality of the CNC based antioxidant system as a biocompatible and sustainable protocol with potential for use in personal care applications.