Green synthesis of rifampicin-loaded copper nanoparticles with enhanced antimicrobial activity.

The antimicrobial properties of copper and rifampicin-loaded copper nanoparticles were investigated using four strains: Staphylococcus aureus, Escherichia coli, Bacillus pumilis and Pseudomonas fluorescens. Spherical-shaped copper nanoparticles were synthesized via green reduction method from the peppermint extract. It was found that adsorption of rifampicin on the copper nanosurface enhances its biological activity and prevents the development of resistance. The interactions between rifampicin-copper nanoparticles and bacteria cells were monitored using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). It was proven that loaded with rifampicin copper nanoparticles were able to damage the S. aureus cell membrane and facilitate the bacteria biofilm matrix disintegration. Moreover, the DNA decomposition of S. aureus treated with copper and rifampicin-copper nanoparticles was confirmed by agarose gel electrophoresis. The results obtained indicate that adsorption of rifampicin on the copper nanoparticles surface might provide the reduction of antibiotic dosage and prevent its adverse side effects.