Applications of NiFe2O4 nanoparticles for a hyperthermia agent in biomedicine

Self-heating temperature rising characteristics, cytotoxicity, and magnetic properties of NiFe2O4 nanoparticles have been investigated to confirm the effectiveness as an in vivo hyperthermia agent in biomedicine. NiFe2O4 nanoparticles showed both superparamagnetic and ferrimagnetic behaviors depending on particle sizes. The quantitative cytotoxicity test verified that both uncoated and chitosan-coated NiFe2O4 nanoparticles had noncytotoxicity. The solid state 35 nm size NiFe2O4 nanoparticles first exhibited a maximum self-heating temperature of 44.2 degrees C at H(0)f=5.1 x 10(8) A m(-1) s(-1). The physical nature of the self-heating was primarily thought to be due to the magnetic hysteresis loss, Neel rotations, and Brownian rotations of 35 nm size NiFe2O4 nanoparticles. (c) 2006 American Institute of Physics.