Adducts of functionalized Graphene layers with Ag nanoparticles for Antimicrobial applications

Health and environmental impacts of multi-drug resistance (MDR) pathogens are becoming more and more relevant nowadays, thus increasing the need of developing new, safe and effective antimicrobials. This research was focused on the synthesis, the characterization and the evaluation of the antimicrobial and cytotoxic activity of hybrid nanomaterials made up through a simple and sustainable functionalization of three carbon substrates, namely Graphite, Carbon black and Carbon nanotubes, with a pyrrole moiety (SP) and silver nanoparticles (Ag-NP) [1, 2]. The adducts were analyzed by means of thermogravimetric analyses (TGA), transmission electron microscopy (HRTEM) and X-ray diffraction analyses (WAXD), which confirmed the successful functionalization of raw materials. UV-vis spectroscopy and dynamic/electrophoretic light scattering (DLS/ELS) provided information regarding carbon suspensions stability, particles sizes and surface charge. Results from microbiological tests revealed an outstanding enhancement of the antimicrobial activity promoted by the functionalization with Ag nanoparticles, maintaining unaltered the cytotoxic levels exerted by not-functionalized materials. In the light of these results, a possible bactericidal mechanism based on the synergy between mechanical and oxidative stresses at the bacterial membrane level is proposed.