Gas-Phase Production of Multifunctional Composite Nanoparticles by Photoinduced Chemical Vapor Deposition

Nano-scale materials and devices allow for unique interactions that are not possible at larger scales. Magnetic particles below a critical size (∼10 nm) demonstrate distinctive behavior known as superparamagnetism, where particles do not exhibit any net magnetic force outside the presence of an external magnetic field. However, within an alternating magnetic field, as in a magnetic resonance imaging (MRI) machine, superparamagnetic particles give off heat as a result of Brownian and Nee´lian relaxation. Heat produced by the shifting pole orientation can raise the temperature of the tissue sufficient to cause cell death through necrosis or apoptosis [1]. Additionally, combinations of electrically conductive and insulating materials within a single nanoparticle give rise to surface plasmon resonance. The resonance of the plasmon absorption can be tuned based on the relative thicknesses of the two layers. These particles can be used to thermally ablate cancer cells if the resonance is tuned to absorb light from an infrared laser. The penetrating ability of the nanoparticles combined with their capacity to kill cells make them excellent candidates for treatment of conditions such as brain tumors and prostate cancer.