(A), Controlled binding and directed orientation of the IgG onto the silica surface of the SERS NP cluster via coating with protein A/G (top, orange), which exhibits multiple binding sites for the Fc region of the IgG (bottom). In this case, all antigen binding sites are accessible. (B) Localization of PSA by using SERS-labeled PSA antibodies and p63 labeled nanotags on non-neoplastic prostate tissue (C). (D) demonstrates two-color immuno-SERS microscopy for the co-localization of p63 (green) and PSA (red). p63 false-color SERS image overlaid with Raman reporter: 4-MBA (green) and PSA false-color SERS image with Raman reporter: 4-NTB (red) [12, 13].