Bio-Derived Chitosan-Based ZnO/SnO₂ Nanocomposites: Evaluation of Cytotoxic and Biomedical Potential

The present study aims to synthesize a multifunctional nanocomposite, ZnO/SnO₂/CS comprising zinc oxide (ZnO), tin oxide (SnO₂), and crab shell-derived biopolymer chitosan (CS), and evaluate its abilities in antioxidant, antidiabetic, anti-inflammatory, and cytotoxic applications. Cancer is a group of illnesses caused by the uncontrolled growth and proliferation of abnormal cells, is a leading cause of death worldwide, responsible for nearly one in six deaths. The treatment of cancer becomes more complicated when a patient has several comorbidities. There is a need to develop anti-cancer agents with multiple health benefits. The structural, optical, and morphological properties of the synthesized nanocomposite were carried out by XRD, FTIR, FESEM, EDS with mapping, HR-TEM, XPS, and PL spectroscopy. The biomedical potential of the nanocomposite was evaluated by antioxidants (DPPH and superoxide), antidiabetic (α-glucosidase), anti-inflammatory (protein denaturation), and cytotoxicity (MTT) assays. The nanocomposite ZnO/SnO₂/CS revealed 93.86 % and 93.28 % inhibition of free radicals in the DPPH and superoxide radical scavenging assays, with IC₅₀ values of 107.07 ± 0.41 µg/mL and 140.66 ± 1.32 µg/mL, respectively. Similarly, the nanocomposite revealed better antioxidant and anti-inflammatory capability against α-glucosidase and protein denaturation assays with IC₅₀ values of 102.68 ± 0.82 and 131.32 ± 0.97 µg/mL, respectively. The cytotoxicity assay showed an IC₅₀ value of 15.197 ± 1.960 µg/mL for lung cancer cells (A-549) and 18.607 ± 2.641 µg/mL for breast cancer cells (MDA-MB-231). The cell morphological analyses and EtBr fluorescence staining demonstrated the apoptosis induced cell death. The multiple health benefits of the ZnO/SnO₂/CS nanocomposite make it a favourable candidate for further anticancer research.