Antioxidant Single-Walled Carbon Nanotubes

Abstract

Single-walled carbon nanotubes (SWCNTs) and ultrashort SWCNTs (US-SWCNTs) were functionalized with derivatives of the phenolic antioxidant, butylated hydroxytoluene (BHT). By using the oxygen radical absorbance capacity (ORAC) assay, the oxygen radical scavenging ability of the SWCNT antioxidants is nearly 40 times greater than that of the radioprotective dendritic fullerene, DF-1. In addition, ORAC results revealed two divergent trends in the antioxidant potential of SWCNTs, depending on the type of functionalization employed. When existing pendant sites on US-SWCNTs were further functionalized by either covalent or noncovalent interactions of the existing pendant sites with a BHT derivative, the amount of BHT-derivative loading proportionately increased the overall antioxidant activity. If, however, functionalization occurred via covalent functionalization of a BHT-derivative directly to the SWCNT sidewall, the amount of BHT-derivative loading was inversely proportional to the overall antioxidant activity. Therefore, increasing the number of pendant sites on the SWCNT sidewalls by covalent functionalization led to a concomitant reduction in ORAC activity, suggesting that the nanotube itself is a better radical scavenger than the BHT-derivatized SWCNT. Cytotoxicity assays showed that both nonfunctionalized and BHT-derivatized SWCNTs have little or no deleterious effect on cell viability. Therefore, SWCNTs may be attractive agents for antioxidant materials and medical therapeutics research.

On the applicability of cluster models to study the chemical reactivity of carbon nanotubes

“…In recent experimental 7 and theoretical [8][9][10][11][12][13][14][15] investigations, it has been demonstrated that nanotubes [8][9][10][11][12][13] and graphene [14][15][16] have excellent radical scavenging properties. In spite of that, there seems to be controversy regarding the effect of chirality on the addition energies determined for semiconducting and metallic nanotubes.…”

A versatile, solvent-free methodology for the functionalisation of carbon nanotubes

“…The grafting ratios and average oligomer chain lengths varied significantly with the monomer used and reached values up to 8 wt% and around 70 monomeric units, respectively, for the most reactive compounds (Table 1). Monomeric units Parent CNTs n/a n/a n/a Air-exposed CNTs n/a n/a n/a Compared to both the untreated parent material and the "air-exposed" control sample, the solvent dispersibility of the modified CNTs improved significantly, in a range of solvents ( [44][45][46] For instance, the gold-tagged CNTs, presented in Figure 6 could be useful materials in their own right as (electro)catalyst.…”

The Advances of Carbon Nanotubes in Cancer Diagnostics and Therapeutics

“…According to some reports, the aromatic structure and electronic characteristics of CNTs can be preserved via noncovalent attachment. Due to chemical treatment, the emergence of charge on the surface of nanotube is able to adsorb the molecules via ionic interaction [35,47,48]. Some researchers have also been devoted to the debunching and solubilization of CNTs; they used nucleic acids and amphiphilic polymers on the basis of the p-p stacking interactions between the CNTs surface and aromatic bases/amino acids appearing in the structural backbone of these functional biomolecules.…”