13-04-2017, 04:03 PM
Biologically synthesized nanoparticles have been widely used in the medical field. Research in nanotechnology highlights the possibility of green ecological ways to produce technologically important nanomaterials. The present study focuses on the biological synthesis of zinc oxide nanoparticles (ZnO-NPs) by zinc acetate and sodium hydroxide using the biocomponents of the leaves of Catharanthus roseus. The samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDAX) and FT-Raman Spectroscopy. The synthesized ZnO-NPs were found to be spherical in shape with an average size of 23 to 57 nm. These ZnO-NPs were evaluated for antibacterial activity. The maximum diameter of the zones of inhibition around the ZnONPs disc used for Bacillus thuringiensis indicates resistance to ZnO NPs followed by Escherichia coli. Among the four bacterial species examined, Pseudomonas aeuroginosa is more susceptible compared to three other species. It is concluded that the biological synthesis of ZnO NPs is very fast, easy, cost-effective and environmentally friendly and without any side effects and ZnO Nps can be used for the preparation of antibacterial formulations.
The aqueous extract of C. roseus leaf was added to 0.025 M aqueous zinc acetate and the pH was adjusted. The resulting solution was pale white. After stirring, the precipitate was washed with distilled water followed by ethanol to be freed of impurities. The solution was dried under vacuum and used for characterization of ZnO NP.
Synthesis of nanoparticles by using the stem extract
Into a 250 ml conical flask, 10 ml of R. graveolens (RG) stem extract are added dropwise to 90 ml of 0.1 M of zinc nitrate solution under continuous vigorous stirring at room temperature for 4- 5 hr. After 2.0 M NaOH solution is added dropwise and then continuous stirring, finally a pale yellow solution is formed, and then incubated overnight at room temperature; The white precipitate is deposited on the bottom of the conical flask. This white precipitate is washed with distilled water for 2-3 times and then washed again with methanol for 3-4 times and air dried. The dried Zn-Nps were discarded for further analysis.
The aqueous extract of C. roseus leaf was added to 0.025 M aqueous zinc acetate and the pH was adjusted. The resulting solution was pale white. After stirring, the precipitate was washed with distilled water followed by ethanol to be freed of impurities. The solution was dried under vacuum and used for characterization of ZnO NP.
Synthesis of nanoparticles by using the stem extract
Into a 250 ml conical flask, 10 ml of R. graveolens (RG) stem extract are added dropwise to 90 ml of 0.1 M of zinc nitrate solution under continuous vigorous stirring at room temperature for 4- 5 hr. After 2.0 M NaOH solution is added dropwise and then continuous stirring, finally a pale yellow solution is formed, and then incubated overnight at room temperature; The white precipitate is deposited on the bottom of the conical flask. This white precipitate is washed with distilled water for 2-3 times and then washed again with methanol for 3-4 times and air dried. The dried Zn-Nps were discarded for further analysis.