Production of magnetic microspheres by ultrasonic atomisation

Magnetic microspheres, with mean particle sizes from 23 to 32 μm were produced by the ultrasonic atomisation of a suspension of magnetite particles, of approximately 200 nm diameter, in a solution of poly–l–lactic acid (PLLA). The mean particle diameter and the width of the particle diameter distribution both increased with increasing magnetite concentration. The particles appear to be suitable for magnetic hyperthermic treatment of liver cancers, with the hysteresis loop areas increasing linearly with nominal magnetite concentration up to 30 wt% magnetite.