Enhanced mechanical properties of hBN-ZrO₂ composites and their biological activities on Drosophila melanogaster: synthesis and characterization

In this study, six compositions in the system [x(h-BN)-(100 - x)ZrO₂] (10 ≤ x ≤ 90) were synthesized by a bottom up approach, i.e., the solid-state reaction technique. XRD results showed the formation of a novel and main phase of zirconium oxynitrate ZrO(NO₃)₂ and SEM exhibited mixed morphology of layered and stacked h-BN nanosheets with ZrO₂ grains. The composite sample 10 wt% h-BN + 90 wt% ZrO₂ (10B90Z) showed outstanding mechanical properties for different parameters, i.e., density (3.12 g cm^-3), Young's modulus (10.10 GPa), toughness (2.56 MJ m^-3), and maximum mechanical strength (227.33 MPa). The current study further checked the in vivo toxicity of composite 10B90Z and composite 90B10Z using Drosophila melanogaster. The composite 10B90Z showed less cytotoxicity in this model, while the composite 90B10Z showed higher toxicity in terms of organ development as well as internal damage of the gut mostly at the lower concentrations of 1, 10, and 25 μg mL^-1. Altogether, the current study proposes the composite 10B90Z as an ideal compound for applications in biomedical research. This composite 10B90Z displays remarkable mechanical and biological performances, due to which we recommend this composition for various biomedical applications.