ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Prooxidant, antioxidant and biological activity of nanocomposites of reduced graphene oxide, silver, copper and their combinations

Elitsa L. Pavlova, Iliana A. Ivanova, Anna D. Staneva, Aneliya S. Kostadinova, Diana G. Kichukova, and Lyubomira D. Yocheva

Faculty of Physics, Sofia University “St. Kliment Ohridski, Sofia, Bulgaria

E-mail: elli_pavlova@abv.bg

Received: 3 April 2022  Accepted: 8 July 2022

Abstract:

The study aimed to evaluate the prooxidant, antioxidant and biological activities of newly synthesized nanocomposites of reduced graphene oxide (RGO) and its combinations with silver and copper by luminescent and microbiological assays. The antimicrobial activity was tested in a liquid medium during 24 h against Escherichia coli and Staphylococcus aureus. The Gram-positive bacteria were more resistant than the Gram-negative. Strongest antibacterial effect was demonstrated by the graphene nanocomposite decorated with silver and copper. The cubic silver nanoclusters size 30 nm showed better bacteriostatic effect than the spherical nanoparticles on reduced graphene sheets with 43 nm diameter. The eukaryotic cell cytotoxicity effect was evaluated with two cell lines—MDCK kidney epithelium noncancerous cells and A549 lung cancerous epithelium cells, tested in cell culture medium for 24 h. Our results showed that RGO Ag:Cu had stronger cytotoxic effect on eukaryotic cells. We have discovered that the cancerous A549 cells show stronger sensitivity to the nanomaterials than the noncancerous MDCK-cells. The pro- and antioxidant activity of all nanomaterials was studied according to the free-radical oxidation reactions (pH 7.4 and pH 8.5) in the following chemiluminescent model systems: (1) chemical, with Fenton`s reagent (H<sub>2</sub>O<sub>2</sub>-FeSO<sub>4</sub>), for the generation of hydroxyl radicals (<sup>.</sup>OH), (2) chemical, with oxidant hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), (3) chemical (NAD.H-PhMS), for the generation of superoxide radicals (O<sub>2</sub><sup>.−</sup>). All tested nanomaterials presented definitive antioxidant activity in both tested media at neutral and alkaline pH. The only exception was RGO Ag nanoparticles, sized 30 nm, that exhibited less than 10% prooxidant activity in the Fenton`s system, at pH 8.5. Those results support the idea to use such nanomaterials in body implants.

Keywords: Graphene oxide; Silver; Copper; Nanoparticles; Toxicity

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02360-4

Chemical Papers 76 (11) 6789–6800 (2022)