Synthesis of Metallic / Metallic Oxide Nanoparticles in Surfactant Shell and Investigating their Anti- bacterial Activities

With the increasing bacterial resistance for antibiotics, the demand for alternative agents is increased. Scientists go on for nanoparticles, a nanoscale material ranging from 1-100 nanometers. One of the famous nanoparticles is zinc oxide nanoparticle which is one of metal oxide nanoparticles that possess many properties such as semiconducting properties, antibacterial activity. Cobalt oxide nanoparticles, on the other hand, have less antibacterial activity research concerns. In this study, the two kinds of the nanoparticles, ZnO and CoO nanoparticles, were synthesized using chemical reduction method in different forms: the nanoparticle alone, the nanoparticle stabilized in tetra octyl ammonium bromide (TOAB) and the nanoparticle stabilized in surfactants and mixed with three diffrent types of antibiotic; Amoxicillin, Cephalexin and Streptomycin. Then, the antibacterial activity of prepared nanoparticles were studied on three bacterial strains, S. aureus, B. subtilis and E. coli. Antibacterial activity of each preparation was tested separately. Antibacterial activity of the synthesized nanoparticles showed a noticeable increase when stabilized in TOAB surfactant. Interestingly, the antibacterial activity is several times increased by the addition of the antibiotics to the NPs stabilized in TOAB; it seems that the nanoparticles stabilized in TOAB and mixed with antibiotics have synergestic effect in inhibition of bacterial growth. Interestingly, the results indicated that CoO NPs stabilized in surfactants and mixed with antibiotics have more significant increase in the antibacterial activity against the three types of bacteria in comparison to the comparable ZnO nanoparticles preparation. Therefore, this study opened the new door to find the magic cure against the multidrug resistant bacterial strains with the lowest toxic effect of the usage of high doses of the different antibiotics and nanoparticles. Key words: Zinc oxide nanoparticles, Cobalt oxide nanoparticles, Tetraoctyl ammonium bromide, S. aureus, B. subtilis, E. coli, Amoxicillin, Cephalexin, Streotomycin.