Fabrication of surface-enhanced Raman scattering (SERS) nanostructures with both high sensitivity and spectral reproducibility, which are key requirements for routine SERS quantitative (sensing) applications, is a great challenge. Here we report on the multilayered design of SERS-active substrates formed by uniform Ag nanoislands stabilized by a magnetron-sputtered polytetrafluoroethylene (msPTFE) film of nanometre thickness. The preparation of large scale (∼20 cm²) nanostructures with long (∼months) time stability was fast (∼minutes), cheap and repeatable. SERS performance of our substrates was subsequently improved by step-by-step optimisation of the fabrication procedure and introduction of the additional silver layer, separating the supporting glass from the msPTFE film, which contributed to the total enhancement factor by another order of magnitude. Such substrates provided high SERS sensitivity with a SERS enhancement factor of about 2 orders of magnitude larger than commonly reported in the literature for Ag nanoislands grown directly on glass. The limits of detection were determined as ∼1 × 10⁻¹⁰ M, 1 × 10⁻⁷ M and 1 × 10⁻⁶ M for testing analytes methylene blue (MB), 5,10,15,20-tetrakis(1-methyl-4-pyridyl)porphyrin (H₂TMPyP) and cysteine, respectively. SERS substrates showed excellent spectral reproducibility both across a single substrate and different substrate batches. The relative standard deviation (RSD) of the SERS signal did not exceed 20% for different concentrations of MB and H₂TMPyP, respectively. Therefore, Ag nanoislands stabilized by the msPTFE film are due to high sensitivity, stability and excellent spectral reproducibility very promising substrates for SERS biomolecular quantitative (sensing) applications.

Urgent need for innovative and effective antibacterial coatings in different fields seems to have triggered the development of numerous strategies for the production of such materials. As shown in this short overview, plasma based techniques arouse considerable attention that is connected with the possibility to use these techniques for the production of advanced antibacterial Ag/plasma polymer coatings with tailor-made functional properties. In addition, the plasma-based deposition is believed to be well-suited for the production of novel multi-functional or stimuli-responsive antibacterial films.