Antioxidant studies of fullerene and metallofullerene derivatives and fluorescence studies of terbium-containing metallofullerene derivatives

Fullerenes and metallofullerenes have been discovered to have a lot of applications in the biomedical area, for instance, they have been shown to have antioxidant, anti-virus, anti-cancer, immunological properties, etc. However, the hydrophobicity nature of fullerenes and metallofullerenes raises the need for functionalized hydrophilic fullerenes and metallofullerenes. Also, the advancement of the purification techniques of fullerenes and metallofullerenes makes the isolation of new fullerenes and metallofullerenes possible. Therefore, discovering the biomedical applications of these newly found fullerenes and metallofullerenes is also of vital importance. In Chapter 1, we provided a comprehensive background on the history of fullerenes and metallofullerenes, synthesis and purification methods of fullerenes and metallofullerenes, and some of their biological applications, including antioxidant applications and fluorescence applications. Some important fullerene and metallofullerenes and milestones in this area were also discussed. In Chapter 2, we demonstrated the antioxidant and anti-inflammation ability of a conjugate, FIFIFK(Cy5)PEG24K(NH2)CONH2-C60, that consisted of a peptide that binds specifically to a formyl peptide receptor-1 (FPR-1), which expresses on activated macrophages, and a carboxyl-group-functionalized C60, which is the first discovered and most used fullerene is history. We showed that the fullerene-peptide conjugate had great ability as a radical scavenger and to reduce the volume of inflammatory tissue. In Chapter 3, we demonstrated the antioxidant and anti-inflammation ability of several metallofullerene derivatives, including amino-Gd3N@C80, amino-Sc3N@C80, carboxy-Gd3N@C80, and carboxyl-Sc3N@C80. Amino-group-functionalized metallofullerenes were found to have higher radical scavenging ability and anti-inflammation ability. In Chapter 4, we developed fluorescent metallofullerene derivatives, including Tb3N@C80(NH2)9(OH)4NO2 and Tb3N@C80(CH2CH2COOH)21(OH)18. The fluorescence properties of the derivatives of fullerenes or metallofullerenes were normally realized by the addition of fluorescent moieties on the carbon cage of fullerenes or metallofullerenes. However, the fluorescence of our newly developed metallofullerene derivative was realized by the tri-terbium nitride cluster inside the carbon cage. This saved the multi-step synthesis of the fluorescence probe and maintained the simplicity of the structure of the metallofullerene derivative. These derivatives of terbium-containing metallofullerene also showed radical scavenging ability towards hydroxyl radicals. In Chapter 5, we developed another fluorescent Tb3N@C80 derivative, Tb3N@C80[DiPEG2000]. The advantage of this fluorescent metallofullerene derivative was that it was easier to purify compared to small-functional-groups-functionalized Tb3N@C80 derivatives. This newly developed fluorescent Tb3N@C80 derivative also showed great fluorescent ability and radical scavenging ability. In Chapter 6, we provided a summary of the studies on the antioxidant and fluorescent properties of fullerenes and metallofullerenes' derivatives that were discussed in this dissertation.