Magnetic retardance and magnetic heating in dextran-citrate coated ferrofluids

The Fe3O4 magnetic nanoparticles (MNPs) coated by citrate and dextran prepared by the co-precipitation method was described. Influence induced by the mass variation of coating dextran was investigated. Magneto-optical birefringence of biocompatible dextran-citrate (DC) coated ferrofluids (FFs) was obtained by the Stokes polarimeter. Next, uniform design method was used to find the DC coated FF with high retardance and low dichroism. Retardance of the optimized A9 sample with 1 g/ml was measured as 56.7898 degrees (dichroism was 0.3716) under 64.5 mT. Further, magnetic heating effect in alternating magnetic field was investigated. When the concentrations of A9 were of 2 mg/ml and 50 mg/ml, under the external alternating magnetic field with applied apparent current of 210 A, after heating 5 s the temperature of the DC coated FFs was greater than 47 degrees C, respectively, reached the requirements for the magnetic inductive heating treatment of cancer tumor. The potential of DC coated FFs in hyperthermia was highly evaluated.