Green and cost-effective synthesis of copper nanoparticles by extracts of non-edible and waste plant materials from Vaccinium species: Characterization and antimicrobial activity

The aim of this work was the green synthesis of copper nanoparticles (Cu-NPs) using aqueous extracts of bilberry (Vaccinium myrtillus L.) waste residues from the production of fruit juices and non-edible “false bilberry” fruits (Vaccinium uliginosum L. subsp. gaultherioides) from different cupric salts. The CuNPs were characterized by transmission electron microscopy and photoelectron spectroscopy. The composition of polyphenols of the bilberry extracts and their role in CuNPs synthesis was evaluated by spectrophotometric methods and high-performance liquid chromatography coupled with tandem mass spectrometry. The antimicrobial activity of Cu-NPs, berry extracts, and cupric ion solutions were analysed by broth microdilution and time-kill assays, on prokaryotic and eukaryotic models. Cu-NPs from the green synthesis here proposed can be considered as a cost-effective sanitization tool with a wide spectrum of action.