Homogeneously alloyed nanoparticles of immiscible Ag-Cu with ultrahigh antibacterial activity

Immiscible bimetallic Ag-Cu system has been synthesized by the pulsed plasma in liquid method with a graph of one pulse duration. Herein, by combining X-ray power diffraction, K-edge X-ray absorption near edge structure and high-resolution transmission electron microscopy, our results indicate that homogeneously alloyed Ag-Cu nanoparticles (Ag-Cu NAs) have the average diameter about 2.1 nm, composed by 48.5 at% Ag and 51.5 at% Cu with chemical analysis and the estimated lattice parameter was 3.873 Å. The antibacterial property of Ag-Cu NAs was detected against E. coli and S. aureus strains according to the colony formed abilities of bacteria on agar plates covered with the nanoparticles. With very short incubation period, Ag-Cu NAs completely inhibited the E. coli and S. aureus growth at an ultralow concentration. The mechanism of antibacterial property of Ag-Cu NAs was performed by the inductively coupled plasma-atomic emission spectrometry and the plane wave pseudopotential method implemented in the CASTEP package based on the density functional theory. The Ag⁺ dissolution is correlated with antibacterial activity for Ag-Cu NAs-assisted antibacterial treatment. These findings obtained revealed that our Ag-Cu NAs could be served as a containing material of numerous bacteria-free products in order to avoid their bacterial contamination.