Size- and Morphology-Dependent Antibacterial Properties of Cuprous Oxide Nanoparticle and Their Synergistic Antibacterial Effect

Cuprous oxide nanoparticles with diverse morphology and particle size were prepared through reductive solution chemistry routes under alkaline condition. The standard minimal inhibitory concentration (MIC) test against Escherichia coli indicated that both size and morphology of cuprous oxide nanoparticles played important role in their antibacterial performance. Cuprous oxide nanoparticles with smaller size (∼50 nm) exhibited better antibacterial activity than those with larger size (250∼350 nm); spherical cuprous oxide nanoparticles were found to be superior to the cubic ones in the bacterial killing process. In addition, the synergistic antibacterial effect of cuprous oxide nanoparticles in the presence of another antibacterial agent, ascorbic acid (AA), was investigated. Experimental results showed that the antibacterial capacity of cuprous oxide nanoparticles was significantly improved in the presence of ascorbic acid (0.1 wt%). The probable mechanism underlying the synergistic antibacterial activity has been discussed in detail. All the experimental results indicated that the developed low-cost antimicrobial mixture holds promising application potential.