Analysis of the Fluorescence Intensity Enhancement by Magnetic- Plasmonic Nanoparticles for Biomarkers Detection

A dependence of the intensity of the fluorescent signal on the distance between a fluorescence dye molecule and a surface of a small magnetic (Fe304) nanoparticle to the surface of a large plasmonic magnetic nanoparticle (covered by a small plasmonic layer) is analyzed. Simulations have shown that a large enhancement can be achieved by coating large magnetic nanoparticles with a thin metal layer for plasmon enhancement of the field intensity at the dye molecule area. It is shown that plasmon nanoparticles can tenfold increase the intensity of fluorescence. For the best fluorescence enhancement, the distance of a dye molecule from a small pure magnetic nanoparticle should be at least 5 nm. In another case, strong dissipation losses in magnet medium result in strong fluorescent quenching and loss in fluorescence intensity.