Phyto-mediated synthesis of CeO2/ZrO2 nanocomposite: A potential performer for multifarious biomedical applications

Abstract

This study reports the synthesis of CeO₂/ZrO₂ nanocomposite via the biogenic route utilizing Citrus limonium (lemon juice) along with the CeO₂ and ZrO₂ nanoparticles for comparative purposes. The XRD analysis confirms the effectual formation of phase-pure and good crystalline CeO₂/ZrO₂ nanocomposite, exhibiting a mixed cubic and tetragonal structure with an average crystallite size of 66 nm. FT-IR analysis exposes the characteristic metal-oxygen bonds along with organic functional moieties. The UV-visible diffuse reflectance results show strong absorption from 200 to 420 nm for the CeO₂/ZrO₂ nanocomposite, with a bandgap of 3.22 eV. The surface morphology of the nanocomposite reveals a foundation of irregular, block-like ZrO₂ structures, with affixed smaller aggregates of CeO₂ on the ZrO₂ surface with interstices between them. Furthermore, the co-occurrence of Ce³⁺ and Ce⁴⁺ oxidation states, along with Zr⁴⁺ and surface oxygen species, significantly boosts the nanocomposite's redox activity. Antibacterial assays demonstrated that the CeO₂/ZrO₂ nanocomposite exhibited the highest inhibition zones in Salmonella typhi and Bacillus subtilis, surpassing individual nanoparticles. Antioxidant studies show 83% DPPH radical scavenging activity and 88% superoxide anion free radical scavenging activity. The antidiabetic activity study shows 89% inhibition of α-amylase and 86% inhibition of α-glucosidase at 950 μg/mL, which is better than the individual nanoparticles. This insightful study emphasizes the compelling potential of CeO₂/ZrO₂ nanocomposite for advancing therapeutic strategies and significantly improving clinical outcomes across a range of medical conditions.