Green synthesis nanocomposite GO/ZnFe2O4 with water extract of Teucrium polium and evaluation of its anti-bacterial and cytotoxicity activities

Materials based on graphene oxide (GO) and zinc ferrite nanoparticles (ZnFe₂O₄ NPs) have attracted considerable attention due to their large surface area, structural versatility, and potential biological functionality. In this study, GO NPs, ZnFe₂O₄ NPs, and a GO/ZnFe₂O₄ nanocomposite (GO/ZnFe₂O₄ NC) were green-synthesized and systematically characterized, focusing on their structural, magnetic, optical, and biological properties. Structural and compositional features were analyzed using X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray analysis (EDX), and vibrating sample magnetometry (VSM), while scanning electron microscopy (SEM) was employed to investigate the morphology of the materials. The antibacterial activity of the synthesized materials was evaluated against Escherichia coli and Staphylococcus aureus. Both ZnFe₂O₄ NPs and the GO/ZnFe₂O₄ NC exhibited notable antibacterial effects, with the nanocomposite showing superior inhibitory performance against both bacterial strains. Furthermore, the GO/ZnFe₂O₄ NC demonstrated significant cytotoxic activity against HeLa cancer cells, with an IC₅₀ value of 13.58 µg/mL, while exhibiting considerably lower toxicity toward normal fibroblast cells (IC₅₀ = 158.5 µg/mL), indicating selective anticancer potential. Gene expression analysis revealed that treatment with the GO/ZnFe₂O₄ NC significantly upregulated the pro-apoptotic genes BAX and Caspase-3, while markedly downregulating the anti-apoptotic gene Bcl-2, suggesting apoptosis as a possible mechanism underlying its cytotoxic effects.