Surface-enhanced Raman scattering (SERS) technique is of greatinterest because the Raman signal of the biomolecules and bacteria canbe enhanced by several orders of magnitude. The enhancement resultsfrom the strong optical intensity localized between the surfaces ofmetallic nanostructure. Typically, noble metal of silver (Ag) or gold(Au) nanoparticles (NPs) with various sizes, shapes and assemblies havebeen proved to be highly active SERS substrates. Therefore, SERS becomesa powerful analytical tool capable of identifying and detectingvarious analytes (such as biomolecules, environmental pollutants andmicroorganisms) because its unique vibrational signatures are associatedwith chemical and structural information