Surface-enhanced Raman scattering (SERS) spectroscopy can lead to the fabrication of high-sensitivity label-free sensors for detection purposes in many fields, such as biomedical diagnostics and therapy monitoring, but also agricultural and environmental monitoring. The electromagnetic enhancement plays an important role in the SERS effect; the resonant excitation of Localized Surface Plasmons (LSPs) of noble metal nanoparticles (NPs) – in the regions close to their surface – is the main reason of the scattered light enhancement. Such effect is strongly dependent on the type, size, shape, inter-particle distance and aggregation state of the NPs. Recently, the fabrication of tuneable plasmonic nanostructures constituted by Ag NPs on flexible elastomeric polydimethylsiloxane (PDMS) matrices has been reported.