A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1  

作　　者：LI JinHua PAN YongXin LIU QingSong QIN HuaFeng DENG ChengLong CHE RenChao YANG XinAn 

机构地区：[1]Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China [3]Franco-Chinese Biomineralization and Nano-structures Laboratory, Beijing 100029, China [4]State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [5]Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China

出　　处：《Chinese Science Bulletin》2010年第1期38-44,共7页

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 40821091 and 40325011);Hundred Talents Program of the Chi-nese Academy of Sciences and Marie-Curie Fellowship (IIF) Return Phase of (Grant No. MIF1-CT-2005-007555)

摘　　要：The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Its δ-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity and δ-ratio (1.5), due to increasing three-dimensional magnetostatic interactions and collapse of magneto-some chains. These observations provide useful insights into applications of the biogenic magnetite (magnetosomes) in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magneto- somes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Its 8-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity and δ-ratio （1.5）, due to increasing three-dimensional magnetostatic interactions and collapse of magnetosome chains. These observations provide useful insights into applications of the biogenic magnetite （magnetosomes） in magnetic nano-materials and magnetofossils in the paleornagnetic and environmental magnetism.

关 键 词：磁悬浮 细胞 磁特性 弱相互作用 生物医学应用 纳米生物技术 磁性纳米材料 生物材料 

分 类 号：O572.241[理学—粒子物理与原子核物理] TH133.3[理学—物理]