Co-assembled ZnO-Fe₂O_3x-CuO_x nano-oxide materials for antibacterial protection

Abstract

Metal oxide nanoparticles (MONPs) have been increasingly reported to possess diverse industrial and biomedical applications. Herein, we synthesized secondary (CuO, Fe₂O₃ (FeO), ZnO), ternary (ZnO/CuO-FeO_x) and quaternary (ZnO-CuO-FeO_x) co-assembled core-shelled MONPs by (co-)precipitation technique, characterized the synthesized MONPs and consequently investigated their antibacterial capacity. The UV-Vis absorption spectra of the prepared MONPs presented experimental band gaps; ZnO of 3.36 eV; ZnO-FeO_x (x = 0.1; x = 0.5) with 3.38 eV and 3.37 eV; and ZnO-FeO_x-CuO_x (x = 0.1; x = 0.5) of 3.36 eV and 3.36 eV band gaps respectively. Thermogravimetric analysis revealed the stability of the prepared MONPs, by the presented total mass lost (%): ZnOFeO_0.5 (1.34) > ZnOFeO_0.1 (1.93) > ZnOFeO_0.1CuO_0.1 (2.12) > ZnOFeO_0.5CuO_0.5 (2.34) > CuOFeO_0.1 (3.78) > CuOFeO_0.5 (4.25) > Fe₂O₃ (4.44) > CuO (6.37) > ZnO (8.69). The XRD peak positions of the secondary MONPs prepared presented hexagonal structures for ZnO, monoclinic structures for CuO and rhombohedral structures for Fe₂O₃ without identified impurity peaks. Finally, the co-assembled MONPs prepared showed that they possessed varied efficiency for protection from different bacterial strains, with Staphylococcus.peumonia growth being the most inhibited, with MONPs treatments CuO > ZnOFeO_0.5CuO_0.5 > CuOFeO_0.5 > ZnOFeO_0.1CuO_0.1 > Fe₂O₃ > ZnOFeO_0.5 > ZnO.

GRAPHICAL ABSTRACT

Keywords:

• Metal oxide
• nanoparticles
• co-precipitation
• antibacterial
• zinc oxide
• copper oxide
• hematite

Additional information

Funding

The financial assistance of the University of Zululand and the National Research Foundation, South Africa through the South African Research Chair Initiative (SARChI) is hereby acknowledged. SJO thanks the National Research Foundation (NRF) for funding under South African Research Chair for Nanotechnology.