Application of metal-enhanced fluorescence technology in evanescent wave fluorescent biosensor

Evanescent wave fluorescent sensors have developed for 30 years. Nonetheless, the technology continues to evolve with new breakthroughs in optics, biochemistry, and chemical engineering. Recently, there have been explosive developments in the Metal-Enhanced Fluorescence (MEF) technology to favorably modify the spectral properties and to alleviate photo-physical constraints. We report the development of core-shell nanoparticles with the silver core and SiO₂ shell for potential applications in fiber optic biosensor. The fluorescence intensity of the fluorescence probe (Fluorescein isothiocyanate, FITC) doped core-shell nanoparticles was approximately 50-fold higher than that without core-shell nanoparticles doping. In addition, four different kinds of organic solvents are used in this study and found to have influence on the fluorescence intensity from 1.3 to over 100 times. We conclude that core-shell nanoparticles have capability to enhance the fiber optic sensing through amplifying fluorescence intensity and expect that their potential applications are used in a variety of biological applications.