Abstract:
Oxide semiconductors have attracted increasing interest due to their potential in solving
environmental problems. The development of antibiotic resistance of bacteria is one of the most
pressing problems in world health care. One of the promising ways to overcome microbial
resistance to antibiotics is the use of metal oxide nanoparticles and their dopants. This work aims
to investigate the synthesis of ZnO NPs and Fe doped ZnO NCs (1%,3%, and 5%) using aqueous
Zingibeer Officianale root extract via biosynthesis and evaluation of its antibacterial activities.
The synthesized nanoparticles and nanocomposites were characterized using X-ray diffraction
(XRD), UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), and
Scanning Electron Microscopy (SEM). The optical band gaps were calculated to be Eg = 3.12 eV
and Eg = 3.0 eV for ZnO NPs and 1% Fe doped ZnO NCs respectively. Functional groups
present in the extract, NPs, and NCs were confirmed by FTIR spectroscopy. The average
particle size calculated from the XRD pattern for ZnO NPs and Fe doped ZnO nanocomposite
were 23 and 19.6 nm respectively. SEM analysis showed that ZnO nanoparticles were a granular
size and has irregular spherical morphology while with Fe doped ZnO nanocomposite there is
dispersion with less agglomeration as well as regular distribution of ZnO NPs. The synthesized
NPs and NCs were tested for their antibacterial properties on two Gram-negative bacteria:
Escherichia coli (E.coli) and Salmonella typhi (S.typhi) and two Gram-positive bacteria: Bacillus
cerius (B.cerius) and Staphylococcus aureus (S.aurus). The results showed that ZnO NPs have an
antibacterial inhibition zone of 10 mm and 14 mm against E. coli and S. aureus, and 15 mm and
9 mm against B. cereus and S. typhi respectively at a concentration of 50 mg/mL. Those
synthesized NPs and NCs were more effective on Gram-negative bacteria than gram-positive.
Thus, the bactericidal activity of Fe doped ZnO NCs was more prominent with S. aureus and B.
cerius than S.typhi and E. coli bacteria and when compared to ZnO NPs.
