Multi-walled carbon nanotubes decorated with silver nanoparticles for antimicrobial applications

Great attention has been paid to antimicrobial agents' development to face and control infection transmission of infectious diseases spreading. Decorated multi-walled carbon nanotubes (MWCNTs) with silver nanoparticles (Ag NPs) are useful substances with antibacterial potency that might be used for a wide range of medical applications and water disinfection to limit the spreading of infectious diseases. In this work, silver nanoparticles were loaded on the surface of MWCNTs via the wet-impregnation technique followed by thermal treatment at 450 °C for 4 h in an inert atmosphere. Different ratios of Ag NPs (0, 3, 6, 12 and 24) were loaded on the surface of MWCNTs. The synthesized Ag-MWCNTs nanocomposites were characterized by XRD, XPS, and TEM. The antibacterial efficacy of Ag-MWCNTs nanocomposites was tested towards different microbial strains (bacteria and fungus); P. aeruginosa, E. coli, B. subtilis, S. aureus, C. albicans, and A. niger, which proved the wide spectrum of Ag-MWCNTs. The synthesized nanocomposite showed a higher antimicrobial capability against gram-positive than gram-negative bacteria. Biological studies indicated a large inhibition zone for each bacterial strain that reaches 18.5 mm. SEM and fluorescent microscopy were tested to examine the structural disruption in the outer membranes after incubation with the antibacterial agent. The nanocomposite firmly agglutinated to the surface of the bacterial cells, leading to cells' wrapping, morphology deterioration, and cell death. The inhibition ability of Ag-MWCNTs nanocomposite with a broad spectrum of microorganisms provides exciting opportunities to enhance and maximize potable water disinfection and medical applications to control infectious diseases spreading.