title: Enzyme-mimetic activity of Ce-intercalated titanate nanosheets.
abstract: Colloidal solutions of Ce-doped titanate nanosheets (Ce-TNS) with tiny dimensions (<10 nm) were fabricated through a hydrolysis reaction of titanium tetraisopropoxide and Ce(NO3)3, and their annihilation activity for reactive oxygen species (ROS) was investigated. The obtained Ce-TNS had an akin crystal structure to layered tetratitanate (Ti4O9(2-)) and Ce ions occupied interlayer space between the host layers with a negative charge. The Ce-TNS possessed a superoxide dismutase (SOD) mimetic activity for disproportionation of superoxide anion radicals (O2(-)) as target ROS. It was explained that the annihilation of O2(-) caused a valence fluctuation of Ce ions existing in the interlayer. Moreover, the activity of Ce-TNS exceeded that of CeO2 nanoparticles recently attracting much attention as an inorganic SOD mimic. The superior performance was explained mainly by a high dispersion stability of the Ce-TNS bringing about a huge reaction area. Moreover, the Ce-TNS protected DNA molecules from ultraviolet light induced oxidative damage, demonstrating effectiveness as one of the new inorganic protecting agents for biomolecules and tissues.
authors.affiliation: †Department of Materials Science and Engineering, Faculty of Engineering, Nagasaki University, Nagasaki 852-8521, Japan.
authors.forename: Kai
authors.initials: K
authors.lastname: Kamada
authors.affiliation: ‡Faculty of Agriculture, Saga University, Saga 840-8502, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Soh
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism*; D002563:Cerium / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D053758:Nanoparticles / Q000737:chemistry*; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism*; D014025:Titanium / Q000737:chemistry / Q000378:metabolism*
chemical_list: C009495:titanium dioxide; D002563:Cerium; D014025:Titanium; D013482:Superoxide Dismutase