2022 年 130 巻 11 号 p. 882-888
The magnetic particles with high saturation magnetization and superparamagnetism are needed to detect highly sensitive viruses. The magnetic property of magnetite (Fe3O4) particles synthesized by spray pyrolysis and a subsequent heating process depended on the citric acid content. The magnetic particles consist of nano-sized Fe3O4 crystallite about 10 nm in diameter and the decomposed C with high dispersion. The edge-to-edge separation of the crystallites is about 8 nm. As a result, the superparamagnetic Fe3O4 particles can be synthesized. The saturation magnetization of the synthesized beads (51 A·m2 kg−1) is much higher than that of commercial magnetic microbeads (17 A·m2 kg−1), and the coercive force is 0.24 kA m−1. Superparamagnetism can likely be attained because of the high dispersion of Fe3O4 crystallites below 10 nm in diameter. The Fe3O4 crystallites did not magnetically interact with each other. These unique Fe3O4 particles may hold promise as magnetic particles for enzyme immobilization due to the high possibility of antibody bonding and the ease of separation by magnetic fields.
