ACTA

Characterization of Magnetosomes After Exposure to the Effect of the Sonication and Ultracentrifugation

M. Molčan^a, A. Hashim^a, J. Kováč^a, M. Rajňák^a, P. Kopčanský^a, M. Makowski^b,c, H. Gojzewski^b,d, M. Molokáč^e, L. Hvizdák^e, M. Timko^a
^aInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice, Slovakia
^bInstitute of Physics, Poznan University of Technology, Nieszawska 13A, 60-965 Poznań, Poland
^cMax Planck Institute for Polymer Research, Ackermannweg 10, 55-128 Mainz, Germany
^dMax Planck Institute of Colloids and Interfaces, Department of Interfaces, Wissenschaftspark Potsdam-Golm, Am Mühlenberg 1 OT Golm, 14476 Potsdam, Germany
^eInstitute of Geotourism, Technical University of Košice, Letná 9, 042 00 Košice, Slovakia

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Magnetosomes are intracellular organelles of widespread aquatic microorganisms called Magnetotactic bacteria. At present they are under investigation especially in biomedical applications. This ability depends on the presence of intracellular magnetosomes which are composed of two parts: first, nanometer-sized magnetite (Fe₃O₄) or greigite (Fe₃S₄) crystals (magnetosome crystal), depending on the bacterial species; And second, the bilayer membrane surrounding the crystal (magnetosome membrane). The magnetosomes were prepared by biomineralization process of magnetotactic bacteria Magnetospirillum Magnetotacticum sp. AMB-1. The isolated magnetosome chains (sample M) were centrifugated at speed of 100000 rpm for 4 hours (sample UM) and sonicated at power of 120 W for 3 hours (sample SM), respectively. The prepared suspensions were investigated with respect to morphological, structural and magnetic properties. The results from scanning electron microscopy showed that isolated chains of magnetosomes were partially broken to smaller ones after ultracentrifugation. On the other hand the application of the sonication process caused the formation of individual magnetosomes (unordered in chain). These results were confirmed by coercivity and magnetization saturation measurements.

DOI: 10.12693/APhysPolA.126.198
PACS numbers: 81.07.-b, 75.60.-d, 87.50.Y-, 68.37.-d