Magnetic Au Nanoparticles on Archaeal S-Layer Ghosts as Templates
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AuthorSelenska-Pobell, Sonja; Reitz, Thomas; Schönemann, Rico; Herrmansdörder, Thomas; Merroun, Mohamed Larbi; Geißler, Andrea; Bartolomé, Juan; Bartolomé, Fernando; García, Luis Miguel; Wilhelm, Fabrice; Rogalev, Andrei
InTech Open Access Publisher
Magnetic Au nanoparticlesArchaeal S-layerHigh Resolution Transmission Electron Microscopy (HR-TEM)X-ray Magnetic Circular Dichroism (XMCD)
Selenska-Pobell, S.; et al. Magnetic Au Nanoparticles on Archaeal S-Layer Ghosts as Templates. Nanomaterials and Nanotechnology, 1(2): 8-16 (2011). [http://hdl.handle.net/10481/32289]
SponsorshipPart of this work was supported by the EU in EuroMagNet II (Grant No. 228043) and Magister (Grant No. NMP3‐LA‐2008‐214685). Merroun, M.L. is a “Ramón y Cajal Fellow” of the University of Granada. His contribution was supported by grant No. CGL2009‐09760, and those of the Zaragoza group by project MAT08/1077 of the “Ministerio de Ciencia e Innovación”, Spain. This work corresponds to experiment HE3427 of the ESRF.
Cell‐ghosts representing empty cells of the archaeon Sulfolobus acidocaldarius, consisting only of their highly ordered and unusually stable outermost proteinaceous surface layer (S‐layer), were used as templates for Au nanoparticles fabrication. The properties of these archaeal Au nanoparticles differ significantly from those produced earlier by us onto bacterial S‐layer sheets. The archaeal Au nanoparticles, with a size of about 2.5 nm, consist exclusively of metallic Au(0), while those produced on the bacterial S‐layer had a size of about 4 nm and represented a mixture of Au(0) and Au(III) in the ratio of 40 to 60 %. The most impressive feature of the archaeal Au nanoparticles is that they are strongly paramagnetic, in contrast to the bacterial ones and also to bulk gold. SQUID magnetometry and XMCD measurements demonstrated that the archaeal Au nanoparticles possess a rather large magnetic moment of about 0.1μB/atom. HR‐ TEM‐EDX analysis revealed that the archaeal Au nanoparticles are linked to the sulfur atoms of the thiol groups of the amino acid cysteine, characteristic only for archaeal S‐layers. This is the first study demonstrating the formation of such unusually strong magnetic Au nanoparticles on a non‐modified archaeal S‐layer.