Single domain soft ferromagnetic ferrofluid suitable for intratumoural magnetic hyperthermia

Magnetic hyperthermia is an effective modality for treating cancerous cells selectively at the intracellular level via proper administration, surface tagging and appropriate choice of magnetic nanoparticle. Also, achieving the therapeutic temperature with as much low concentration of nanoparticles, as possible, is desirable. Recently, ferromagnetic nanoparticles or ferrofluid are gaining attention as effective magnetic hyperthermia agents due to their enhanced heating potential under in vivo conditions. In the present work, we have fabricated citrate capped cobalt ferrite ferrofluid via a simple two-step process and investigated the physicochemical, magnetic and induction heating performance. The average size of the synthesized nanoparticle is 9 +/- 4.3 nm which is suitable for intracellular hyperthermia and has the advantage that it can be easily eliminated from the body through renal clearance. The M(T) measurement of the ferrofluid confirmed the soft ferromagnetic behavior. The induction heating potential of the ferrofluid prepared was tested at different concentrations (1, 2, 5 & 10 mg/ml), suspension medium and alternating magnetic fields (15, 30 & 45 kA/m) with a fixed frequency of 316 kHz. Under a viscous environment, 1 mg/ml sample subjected to 45 kA/m reached the hyperthermia temperature within 160 s and the specific loss power was found to be 297 W/g(Co+Fe). Hence, the synthesized ferrofluid is suitable for intratumoural hyperthermia.