3.5 - Magnetic Ultra-Fine Particles Isolated from Bacteria

Abstract

This chapter describes the isolation and cultivation of magnetotactic bacteria, the separation and characterization of magnetic ultrafine particles (UFPs), the immobilization of enzymes and antibodies on the particles, and their incorporation into animal cells. The isolation and cultivation of the fresh water helical magnetotactic bacterium, Aquaspirillum magetotacticum, strain MS-l was reported. Separation of the magnetotactic bacteria was carried out in a semisolid culture containing about 10% filtered sterilized swamp water, organic acids, vitamin, inorganic salts, and agar. The magnetotactic bacteria were mass cultivated in mud. The optimal conditions for cultivating magnetotactic bacteria were obtained through a series of experiments in which the conditions were systematically varied. The effects of carbon and nitrogen sources were evaluated to increase the growth rate of the bacteria. There are a number of reports on the characterization and separation of bacterial magnetic particles. The magnetic fine particles collected from magnetotactic bacteria cultivated in mud were characterized. The collected bacteria were further concentrated and separated using a centrifuge. Various antibodies were immobilized on bacterial magnetic particles and artificial magnetic UFPs, and measurements of the bacterial count and carcino embryonic antigens (CEA) were done. CEA detection was done using CEA antibodies immobilized on bacterial magnetic particles. Ordinary animal cells and microorganisms do not contain magnetic particles. However, if magnetic particles can be introduced into these cells, it would be possible to magnetically move the cells, which would make it possible to treat the cells in a variety of ways.