Open vessel microwave-assisted synthesis of Ag/ZnO hybrid fillers with antibacterial activity

Abstract

A domestic microwave oven was adapted for development of a fast one-pot microwave assisted solvothermal synthesis with the aim of preparation of hybrid Ag/ZnO fillers for prospective medical application. Various hierarchical structures were synthesized in a very simple manner in low-temperature green process. Zinc acetate and silver nitrate were used as sources of Zn2+ and Ag+. Polyvinylpyrrolidone (PVP), glucose, hexamethylenetetramine (HMTA), and aqueous ammonia were used as various reduction and precipitation agents in water solution in this explorative study. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterization reveal hexagonal structure of ZnO particles with the size up to 1 mu m combined with silver spheres with the diameter about 200 nm. In order to evaluate application potential of prepared materials zone diffusion test was used testing of their antibacterial activity. PVA films containing 5 wt.% of various Ag/ZnO hybrid fillers were prepared by solution casting method. Specimens 8 mm in diameter were tested against Gramm positive and Gram negative bacteria in a standard agar diffusion test. All samples exhibit strong antibacterial activity against Staphylococcus aureus as a representative strain of Gramm-positive bacteria, with a mean diameter between 14 and 23 mm of inhibition zone. On the other hand, no measurable extent of diffusion zone diameter was observed in test against Gramm-negative Escherichia coli.