Cytotoxic Activity and Antibiofilm Efficacy of Biosynthesized Silver Nanoparticles against Methicillin-Resistant Staphylococcus aureus Strains Colonizing Cell Phones

The interest for green synthesis of metallic nanoparticles (NPs) has acquired particular attention due to its low toxicity and economic feasibility compared with chemical or physical process. Here we carried out an extracellular synthesis approach of silver nanoparticles (AgNPs) using dried orange peel extract. Characterization studies revealed the synthesis of 25–30 nm AgNPs with distinct morphology as observed in transmission electron microscopes. Dynamic light scattering spectroscopy and Fourier transform infrared spectroscopy analyses further characterized nanoparticles confirming their stability and the presence of functional groups. The biological properties of biosynthesized AgNPs were subsequently investigated. Our results revealed anticancer activity of biogenic silver NPs against the B16 melanoma cell line with an IC50 value of 25 µg/ml. Additionally, the developed AgNPs displayed a considerable antagonistic activity against methicillin-resistant Staphylococcus aureus (MRSA) strains colonizing cell phones, with inhibition zones between 12 and 14 mm and minimum inhibitory concentration values between 1.56 and 12.5 µg/ml. Furthermore, the AgNPs exhibited potent antibiofilm activity against MRSA strains with the percent biofilm disruption reaching 80%. Our results highlighted the efficacy of biosynthesized AgNPs against bacterial biofilms and pointed to the exploration of orange peels as a natural and cost-effective strategy.