Comparative studies of the biological efficacies of Ag and Ag-MgO nanocomposite formed by the green synthesis route

Abstract The present study investigates the changes occurring to the physicochemical and biological properties of silver (Ag) nanoparticles (NPs) before and after conjugating with that of magnesium oxide (MgO). In that view, to form Ag NPs and Ag-MgO nanocomposite, we adopted a green synthesis route that makes use of Citrus paradisi (grapefruit red) extract as a reducing agent and the formed particles are thoroughly characterized for the crystallinity, surface bonding and functionality, morphology, composition, surface charges, etc. From the physicochemical analysis, the successful formation of Ag and Ag-MgO composites are confirmed from the UV–Vis and FTIR spectroscopy, while the TEM indicated the spherical morphology and DLS for the average particle size of 260 nm in solution. Further, on testing the biological efficacy, the Ag-MgO nanocomposite (up to 320 µg/mL) was found to have efficient antibacterial and antifungal activities against Staphylococcus aureus and Candida albicans (respectively). Also, the studies of β-galactosidase enzyme activity resulted that Ag’s composite formation with MgO (Ag-MgO with IC50 of 27.6 µg/mL) is not significantly enhancing the effectiveness as compared to pure Ag NPs (IC50 of 28.6 µg/mL). Also, the in vitro cell viability studies indicated the anticancer activity of Ag-MgO nanocomposite in a dose-dependent manner when tested against the Hela cancer cells was in the concentration range of 1–100 µg/mL (24 h period). Based on the overall analysis, the easy making process by the green synthesis route and inexpensive Ag-MgO nanocomposite can serve as a superior antimicrobial and anticancer ingredient for the development of therapeutic products in the biomedical sector.