Zeolitic Imidazolate Framework-8-Encapsulated Nanoparticle of Ag/Cu Composites Supported on Graphene Oxide: Synthesis and Antibacterial Activity

Thollwana Andretta Makhetha; Sekhar Chandra Ray; Richard Motlhaletsi Moutloali

doi:10.1021/acsomega.9b03215

Zeolitic Imidazolate Framework-8-Encapsulated Nanoparticle of Ag/Cu Composites Supported on Graphene Oxide: Synthesis and Antibacterial Activity

ACS Omega. 2020 Apr 24;5(17):9626-9640. doi: 10.1021/acsomega.9b03215. eCollection 2020 May 5.

Authors

Thollwana Andretta Makhetha^{1

2}, Sekhar Chandra Ray³, Richard Motlhaletsi Moutloali^{1

2}

Affiliations

¹ Department of Chemical Sciences, Faculty of Science, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa.
² DST/Mintek Nanotechnology Innovation Centre - UJ Water Research Node, Faculty of Science, University of South Africa, Private Bag X6, Florida, Science Campus, Christiaan de Wet and Pioneer Avenue, Florida Park, Johannesburg 1710, South Africa.
³ Department of Physics, College of Science, Engineering and Technology, University of South Africa, Private Bag X6, Florida, Science Campus, Christiaan de Wet and Pioneer Avenue, Florida Park, Johannesburg 1710, South Africa.

Abstract

The rational approach motivated the design of novel antimicrobial silver and silver-copper bimetallic nanoparticles contained within zeolitic imidazolate framework-8 supported on graphene oxide (GO), Ag@ZIF-8@GO, and AgCu@ZIF8@GO. In the resultant composites, ZIF-8 was able to prevent the stacking of GO sheets and also acted as a carrier for the nanoparticles within its cavities. GO, on the other hand, acted as an anchoring support enabling uniform dispersion of the nanocomposites, thus eliminating their aggregation. The morphological and physicochemical properties of the composites were determined through a variety of characterization techniques, for example, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, p-X-ray diffraction (XRD), nitrogen sorption, and X-ray photoelectron spectroscopy (XPS). The energy-dispersive system and XPS supplied evidence of the presence of all expected components in the composites. The XRD provided proof of a crystalline, distorted ZIF-8 structure. Ag@ZIF8@GO and Ag-Cu@ZIF-8@GO composites were effective against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria as determined by the disc diffusion method. The role of silver nanoparticles (AgNPs) in the antibacterial activity of both Ag@ZIF8@GO and AgCu@ZIF8@GO was highlighted as crucial in the probable pathway in the antimicrobial activity of the composites.