<p><?tk 4?>Nanocomposites have potential applications in the biomedical field. The growing use of nanomaterials in biomedical intervention raises concern about its potential cytotoxicity and oxidative stress. Systemic in vivo toxicity assessment of nanomaterial is essential prior to clinical application. Calcium functionalized silicon dioxide nanocomposite (Ca²⁺/SiO₂) was synthesized using the sol-gel method and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The surface charge of the nanocomposite was analysed using zeta potential measurement. The cytotoxicity of the nanocomposite was evaluated using MTT assay in L929 fibroblast cells. The toxicity of the material was further investigated in <i>Drosophila melanogaster</i> (fruit fly) model using behavioural assays (survival, climbing, and crawling) and biochemical analyses (superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione S-transferase (GST), and protein estimation). The results indicate that the Ca²⁺/SiO₂ is non-toxic up to a concentration of 200&#xa0;µg/mL. This study provides a comprehensive evaluation of the biocompatibility of Ca²⁺/SiO₂, suggesting their potential for biomedical applications.</p> Graphical abstract <p></p>