  The radiation stability of biocompatibile magnetic fluid used in nanomedicine
after electron irradiation was studied. Two types of the water-based magnetic
fluids were prepared. The first one was based on the magnetite nanoparticles
stabilized by one surfactant natrium oleate. The second one was biocompatibile
magnetic fluid stabilized with two surfactants, natrium oleate as a first
surfactant and Poly(ethylene glycol) (PEG) as a second surfactant. The
magnetization measurements showed that electron irradiation up to 1000Gy caused
50% reduction of saturation magnetization in the case of the first sample with
only one surfactant while in the case of the second biocompatibile magnetic
fluid, only 25% reduction of saturation magnetization was observed. In the
first magnetic fluid the radiation caused the higher sedimentation of the
magnetic particles than in the second case, when magnetic particles are covered
also with PEG. The obtained results show that PEG behave as a protective
element.
