Nanoparticle-based coatings are a promising approach for the antimicrobial functionalization of polymeric surfaces. The present study focuses on the biofunctional performance of metal nanoparticle coatings. Polyamide thin film composite membranes were used as a model substrate for coating application and evaluation. However, the proposed coating process is chemically non-specific and can be easily transferred to other materials.

Silver, copper, and gold nanoparticles were deposited using plasma-enhanced magnetron sputtering. Different analytical techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the coating morphology and surface composition. The biofunctional performance of the coated polymer surfaces was evaluated by static bacterial suspension tests with P. protegens bacteria.

Metal nanoparticles were shown to have a substantial antimicrobial effect. Bacterial growth on silver and copper coated membranes was reduced by a factor of 10³ compared to the uncoated reference membrane. However, no antimicrobial effect was observed for gold coatings. Major limitations exist with respect to the coating stability in aqueous environment. To achieve a long-lasting antimicrobial effect, the stability of silver and copper nanoparticle coatings needs to be improved.