title: 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.
authors.affiliation: Department of Chemistry and Mechanical Engineering, The Smalley Institute for Nanoscale Science and Technology, Rice University, MS-222, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Lucente-Schultz
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Moore
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Leonard
authors.forename: B Katherine
authors.initials: BK
authors.lastname: Price
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Kosynkin
authors.forename: Meng
authors.initials: M
authors.lastname: Lu
authors.forename: Ranga
authors.initials: R
authors.lastname: Partha
authors.forename: Jodie L
authors.initials: JL
authors.lastname: Conyers
authors.forename: James M
authors.initials: JM
authors.lastname: Tour
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry; D002084:Butylated Hydroxytoluene / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D016166:Free Radical Scavengers; D006801:Humans; D037742:Nanotubes, Carbon / Q000737:chemistry*; D017382:Reactive Oxygen Species
chemical_list: D000975:Antioxidants; D001672:Biocompatible Materials; D016166:Free Radical Scavengers; D037742:Nanotubes, Carbon; D017382:Reactive Oxygen Species; D002084:Butylated Hydroxytoluene