In vitro evaluation of Carica Papaya leaf-derived chitosan-ZnTiO₃-TiO₂ nanocomposites as a dual anticancer and antibacterial agent.

U87 glioblastoma is among the most aggressive and clinically incurable brain tumors, with most patients succumbing within 6 months of diagnosis. Emerging nanotechnology-based therapies, particularly those involving nanocomposite matrices, offer promising avenues for combating these malignancies and associated infections. This study investigated the biological effects of chitosan-modified ZnTiO₃-TiO₂ nanocomposites (CZTTNs), which were prepared via a cost-effective green process using Carica papaya leaf extract as a biogenic reducing agent. This eco-friendly approach facilitated the formation of nanostructures without toxic chemicals. As evidenced by FTIR, the papaya leaf extract contains flavonoids, tannins, polyphenols, terpenoids, and alkaloids, which provide multifunctional groups (-OH, -NH, CC) that were crucial for reducing metal ions and stabilizing the nanocomposites. X-ray diffraction revealed a rhombohedral structure and an anatase phase of the CZTTNs. CZTTNs demonstrated higher antibacterial activity against Gram-positive and Gram-negative bacteria. The CZTTNs also exhibited potent anticancer activity against U87 glioblastoma cells, with an IC₅₀ value of ⁓8.8 ± 0.05 μg/mL, highlighting their potential for cancer therapy. Physical malformation rates and ROS generation in zebrafish embryos treated with control, 1 and 3 mg/mL of CZTTNs were evaluated, showing hatching rates of 95%, 91%, and 90%, respectively. The developed CZTTNs exhibit strong antibacterial and anticancer activities, indicating their potential as a long-term solution for global therapeutic challenges.