Magnetic Gold Composite Nanoshells for Nanomedicine Devices

Abstract

Synthesis and characteristics of magnetic gold nanoshells are investigated and discussed from the viewpoint of photothermal therapy (PTT). Morphological properties of thickness, roughness, surface coverage of the shell, the pore size and so on influence their optical properties and the magnetic properties controlling the conditions of synthesis and thermal treatment. NIR light-absorbing gold nanoshells are successfully fabricated on silica/Fe-Pt core-shell nanoparticles via the two-step seed-mediated growth method using a polymer layer of polyethylenimine (PEI) as an interlayer. The cationic polyelectrolyte PEI with high amine content binds to the negatively charged Fe-Pt nanoshell through electrostatic self-assembly to form a stabilizing polyelectrolyte layer, which is necessary to not only the deposition of Au nanoparticles but also the growth of the uniform gold shell. The surface modification using PEI polymers with lower molecular weight of the Fe-Pt nanoshell leads to the formation of a high-quality gold shell with a smooth and thin morphology being responsible to the appearance of a strong NIR absorption. The photothermal properties are obtained by NIR laser irradiation without any deformation of the nanoshells.