Green-Assisted Synthesis and Multi-Functional Evaluation of TiO₂–ZrO₂–Cu Nanocomposite for Enhanced Antibacterial, Antioxidant, and Anticancer Performance

Abstract

This study presents a novel eco-friendly synthesis approach for multi-metallic TiO₂–ZrO₂–Cu nanocomposites using a facile hydrothermal-assisted and chemical reduction method. Zirconia (ZrO₂) and titania (TiO₂) nanoparticles were synthesized and doped in two compositions (30% and 15% ZrO₂ in TiO₂), followed by integration with copper nanoparticles (CuNPs). The structural, morphological, and optical properties were analyzed using XRD, FTIR, UV-Vis, SEM, and HRTEM techniques. The synthesized materials exhibited high crystallinity and uniform dispersion with particle sizes below 50 nm. Antibacterial evaluation via the disc diffusion assay confirmed significant inhibition zones against both Gram-positive and Gram-negative pathogens, surpassing pure oxides. The nanocomposite also demonstrated superior antioxidant activity through DPPH, FRAP, H₂O₂, hydroxyl radical, and nitric oxide scavenging assays. Furthermore, in vitro MTT assays on MCF-7 breast cancer cell lines revealed dose-dependent cytotoxicity, with induced apoptosis confirmed via Bcl-2 gene suppression and elevated caspase-3 and -9 activities. The catalyst also achieved remarkable dye degradation efficiency against methylene blue and Congo red. The study establishes TiO₂–ZrO₂–Cu nanocomposites as multifunctional materials for biomedical and environmental remediation applications.