Physicochemical robustness of pulse laser ablated silver-copper nanocomposoites against varied bacterial strains

Abstract

Nanocomposites (NCs) of inorganic materials with controlled physicochemical characteristics became beneficial for diverse biomedicine and pharmacology applications. Thus, some new types of crystalline spherical silver (Ag)/copper (Cu) nanocomposites (Ag–CuNCs) were made at various laser fluences (ranged from 0 to 14.15 ± 3.9 J cm−2) using the pulsed laser ablation in liquid (PLAL) approach and characterized for the first time. The structures, morphologies, optical and bactericidal properties of these colloidal NCs were determined and the results for the best sample are presented. These NCs showed distinct surface plasmon resonance absorption bands at 402 and 580 nm accompanied by a blue shift. FTIR spectra verified the dispersion of pure Ag–CuNCs in deionized water and XRD pattern confirmed their crystalline nature. EDX analysis of samples confirmed their high purity with appropriate elemental distribution. HRTEM image of the optimum sample exhibited the presence of spherical Ag–CuNCs of mean diameter ≈ 6 ± 1.3 nm and lattice spacing of 0.073 nm and 0.155 nm. Model simulated optimized structure of Ag–CuNCs reaffirmed their stability and chemically reactive HOMO-LUMO isopotential surface. The antibacterial potential of the produced Ag–CuNCs was evaluated using the inhibition zone diameter (IZD) and optical density (at 600 nm) measurements. The optimum Ag–CuNCs prepared at 14.15 ± 3.9 J cm−2 when tested against E. coli, P. aeruginosa, B. subtilis and S. aureus bacteria showed the IZD of 23, 24, 21 and 22 mm, respectively. It was shown that by tuning the laser fluence, the physicochemical and bactericidal attributes of the proposed Ag–CuNCs can be customized, that may have significant implications for potential uses in nanomedicine.