“…To produce the integrated core/shell or sandwich plasmonic nanostructure, commonly the following three processes should be considered: preparation of the metallic nanostructure, coating of the spacer layer and immobilization of the fluorophore layer. 27,[59][60][61][62][63][64]147 MEF from various geometrical nanostructures have been studied and reported so far, and they can be categorized into two main groups: solution-based colloidal nanoparticles (NPs) 27,31,48,52,54,92,145,150 and periodical/non-periodical plasmonic substrate chip, 45,51,64,74,108,135,151, 152 see Fig. 2.…”