Au/Au Core/satellite particles were electrostatically assembled in a four-step process, which is further illustrated in Figure and contains some modifications to the reported procedure. Firstly, ligand exchange from CTAB to MUTAB is performed on the super-spherical particles. Secondly, the core particles were modified with 4-nitrothiophenol (4-NTP) as a Raman reporter molecule for SERS. Thirdly, core particles were electrostatically assembled with excess satellite particles, and the reaction was quenched with PSS. Finally, a protective polyethylene glycol (PEG) shell was introduced by adding 5 kDa 𝛼-Carboxy-𝜔-mercapto PEG. UV/Vis extinction spectroscopy and transmission electron microscopy (TEM) were performed as quality control. Before using them as immunoSERS labels, a purification step (centrifugation or AFFF) is needed to remove excess satellite particles.