Bifunctional magnetic nanoparticles for early detection and magnetic hyperthermia cancer therapy

Abstract

Magnetic hyperthermia offers promise as cancer therapy. We have tested bimetallic core/shell Fe/Fe3O4 magnetic nanoparticles (MNP) for in vivo diagnosis and targeting of MNP to tumor tissue. We have received the MNP from NanoScale Corporation. These particles have a Dopamine‐PEG layer, to which a porphyrin 'A' is attached; another porhyrin 'B' is also attached to the MNP via a peptide that represents the urokinase cleavage site. MNP were tested in B16F10 melanoma cells and neural stem cells for loading using Ferrozine assay.. For in vivo tumor detection, the MNP were injected intravenously into tumor bearing mice and fluorescence was detected after one and two days. Heat distribution studies were conducted in live mice by injecting MNP into mouse leg; temperatures were measured using a fiber optic probe. Short exposure time hyperthermia studies were conducted by exposing tumor bearing mice to alternating magnetic field (AMF) for 10 min (336KHz frequency and 5KA/m amplitude) after injecting theMNP intratumorally. MNP loaded efficiently into mouse cells with little toxicity. We detected fluorescence in tumors during laser imaging of live mice. Mouse subcutaneous melanomas were markedly attenuated; we observed 76% tumor inhibition after short exposure to AMF. These data indicate that bi‐ functional core shell MNP are effective for hyperthermia therapy and detection of subcutaneous melanoma.