Nanoscale iron particles formed from the metalloprotein-like structures prepared using ferrous ions in the presence of sodium glutamate and bovine serum albumin

Well-defined ferric oxide nanoparticles were prepared by the procedure based on the formation of nanoscale zero-valent iron in the presence of amino acids, where the iron(II) bound to the amino acid ligand was combined with the bovine serum albumin protein matrix. The formation of zero-valent iron formed by the reduction of Fe(II) complex by alanine under argon atmosphere to the Fe(0) surrounded by amino acid and protein structures is proposed. Upon oxidation of this reaction mixture, the formation of various iron oxide nanoparticles was observed. The resulting isolated solid material was analyzed by flame atomic absorption spectroscopy, elemental analysis, SQUID magnetometry, Mossbauer spectrometry, UV–Vis–NIR spectroscopy, transmission electron microscopy, and X-ray microanalysis. The majority of the sample is created by aggregates of tiny randomly oriented nanoparticles of high crystallinity with a particle size from about 4 to 12 nm in diameter and predominant rounded and spherical-like morphology. Transmission electron microscopy confirmed the presence of magnetite in the nanoparticle clusters. Mossbauer spectrometry confirms the occurrence of nanoparticles of Fe3+ oxides/oxohydroxides. The existence of the hysteresis loop at the room temperature observed in SQUID magnetometry measurements indicates the presence of maghemite and/or magnetite nanoparticles.