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Structural Aspects of the Growth Mechanism of Copper Nanoparticles Inside Apoferritin
Author(s) -
Ceolín Marcelo,
Gálvez Natividad,
Sánchez Purificación,
Fernández Belén,
DomínguezVera José M.
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200700891
Subject(s) - chemistry , x ray absorption spectroscopy , extended x ray absorption fine structure , hydroxide , copper , nanoparticle , metal , inorganic chemistry , oxide , ion , metal ions in aqueous solution , metal hydroxide , small angle x ray scattering , absorption (acoustics) , absorption spectroscopy , scattering , nanotechnology , organic chemistry , materials science , physics , optics , quantum mechanics , composite material
It is well known that some of the metal ions remain bound to apoferritin when incubating apoferritin with metal ions. In this study a structural insight, from X‐ray absorption spectroscopy (XAS) and small angle X‐ray scattering (SAXS) experiments, into the mechanism of inorganic core formation is presented. The results indicate that, in the case of Cu II at pH 8, the metal ions bound to apoferritin are in fact Cu II oxide/hydroxide. This Cu II species does not react with the Cu II ‐specific TTMAPP, traditionally used to detect Cu II , because TTMAPP is too large to penetrate the apoferritin channel and interact with the metal ions. EXAFS results suggest that the Cu II precursor can be described as an amorphous network of oxygen/hydroxide‐coordinating polyhedra surrounding the copper ions. XAS results demonstrate that this Cu II ‐oxide/hydroxide species is completely converted into zero‐valent Cu nanoparticles when treated with NaBH 4 . Furthermore, a structural model for the final Cu 0 nanoparticle is offered.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)