Network-like Arrangement of Mixed-Valence Uranium Oxide Nanoparticles after Glutathione-Induced Reduction of Uranium(vi)

Glutathione (GSH), a ubiquitous intracellular reducing tripeptide, is able to reduce hexavalent uranium, U(vi), to its tetravalent form, U(iv), in aqueous media in vitro, inducing the formation of nanocrystalline mixed-valence uranium oxide particles. After the initial reduction to U(v) and subsequent dismutation, the yielded U(iv) rapidly hydrolyses under near-neutral conditions forming 2-5 nm sized nanoparticles. The latter further aggregate to 20-40 nm chain-like building blocks that finally arrange as network-like structures.