Improved fluorescence stability for Fe₃O₄/silica @fluorescein/dense silica structure with double shell

The dyes-doped silica particles have been attracting considerable attention because of their applications in various fields such as anti-counterfeiting, biological imaging, sensor technology, microarrays and optical computing. However, it still remains a challenge to a long-term stable fluorescence property of the dyes-doped silica particles, particularly in simulated biological condition, aroused from the leakage of the dyes out of the silica particles. In this work, Fe₃O₄/silica @fluorescein/dense silica core/shell/shell nanoparticles were synthesized by a two-step procedure. We demonstrate that such a core/shell/shell architecture can improve the fluorescence stability in aqueous solution at room temperature and high temperature due to the protection of dense silica. The findings should make an important contribution to the synthesis of fluorescent nanoparticles with high stability and fluorescence efficiency.