Synthesis and functionalization of polypyrrole-Fe₃O₄ nanoparticles for applications in biomedicine

Superparamagnetic Fe₃O₄ particles are successfully encapsulated inside polypyrrole (PPY) via emulsion polymerization using polyvinyl alcohol as a surfactant. The thus-obtained PPY-Fe₃O₄ nanoparticles have distinct spherical shape and size (80-100 nm in diameter) and are superparamagnetic with high magnetization values and good electrical conductivities. By varying the starting Fe₃O₄ : pyrrole monomer mass ratio, nanoparticles with varying Fe₃O₄ content can be synthesized. These nanoparticles are also cyto-compatible, and due to the electrically conducting PPY they display enhanced specific power absorption rates on the basis of per unit weight of Fe as compared to the seed Fe₃O₄ particles. The surfaces of these nanoparticles can be further functionalized with cell-targeting molecules such as folic acid. The potential of using folic acid-functionalized PPY-Fe₃O₄ nanoparticles in cancer cell targeting was investigated and it was observed that the uptake of these nanoparticles by MCF-7 breast cancer cells is significantly enhanced as compared to non-functionalized ones. Such nanoparticles with cancer cell targeting capability and enhanced specific power absorption rates hold great promise for use in the intracellular hyperthermia treatment of cancer tumors.