Nanocrystalline cellulose-fullerene: Novel conjugates

The covalent grafting of two amino-fullerene C₆₀ derivatives (C₆₀-LC-NH₂ and C₆₀-SC-NH_2, LC=long chain and SC=short chain) onto the surface of TEMPO oxidized nanocrystalline cellulose (NCC-COOH) has been reported for the first time. These hybrids (NCC-LC-C₆₀ and NCC-SC-C₆₀) form stable colloidal suspensions at concentrations up to 0.5mg/mL and act as effective photosensitizers for singlet oxygen production as demonstrated by the oxidation of L-methionine-methyl ester to the corresponding sulphoxide. Using the same approach, in a one-pot reaction both a fluorescent target molecule (FITC-LC-NH₂) and the C₆₀-LC-NH₂ derivative have been successfully attached covalently onto the NCC-COOH surface. These hybrids, which showed no cytotoxicity on MCF-7 human breast cancer cells could be good candidates in photodynamic cancer therapy.