Fig. 1. (A) Schematic of SERS agent following conjugation with the urea based PSMA targeting component. Glu-urea-Lys-linker-NHS was grafted onto the SERS tag surface through amine coupling chemistry to prepare the final SERS agent. The molecular structure of the known PSMA inhibitor N-{[(1S)-1-carboxy-3-methylbutyl) amino]carbonyl}-l-glutamic acid (ZJ43) is also shown.⁵ (B) TEM image of the sandwich SERS tag encoded with 4-nitrothiophenol (NTP). (C) SERS spectra of (i) the SERS tag and (ii) SERS agent exhibiting correspondence with the signature of the Raman reporter molecule. (D) IC₅₀ curves of SERS tag, SERS agent and ZJ43.