Synthesis and Characterization Silver, Zinc Oxide and Hybrid Silver/Zinc Oxide Nanoparticles for Antimicrobial Applications

Silver (Ag) and zinc oxide (ZnO) are well known for both antimicrobial and pro-healing properties. Here, we present a novel method to synthesize Ag and ZnO nanoparticles (NPs), as well as hybrid Ag/ZnO NPs using a custom, temperature controlled microwave assisted technique. Microwave synthesis has been shown not only to enhance the rate of chemical reactions, but also in some cases to give higher product yields over thermal heating. The as-synthesized NPs were characterized by X-ray diffraction (XRD) to study the crystalline structure, composition and purity. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) was used to study particle size, shape, composition and morphology. These results indicated that the as-prepared Ag NPs are spherical in shape and similar to 20 nm in sizes. The ZnO NPs are typically rod shaped and the particle sizes are similar to 20 nm in width and 100 nm in length. These NPs were tested for antibacterial and/or antifungal properties using disc diffusion assays. Results show microwave synthesized NPs inhibit growth of S. aureus, E. coli and C. albicans at 50 mu g/mL treatment concentration. Ag NPs were most effective in inhibiting bacterial and fungal growth at the concentrations tested followed by hybrid Ag/ZnO and ZnO nanoparticles. These results also suggest that the hybridization of ZnO to Ag NPs may reduce the toxicity of Ag NPs. Further studies are needed to understand the functional interaction between the two types of NPs and to improve their ability for biological or biomedical application.