Synthesis and characterization of hydroxyapatite–zinc oxide nanocomposites incorporating rosemary and thyme essential oils for enhanced bone regeneration and antimicrobial activity

The study presents a novel approach to bone regeneration using bioactive nanocomposites. The research focuses on creating hydroxyapatite (HAp) and zinc oxide (ZnO) nanocomposites functionalized with rosemary and thyme essential oils (EOs) to enhance osteogenic and antimicrobial properties. The findings reveal that the incorporation of EOs not only improves biocompatibility by reducing Zn-induced cytotoxicity but also enhances antimicrobial activity, particularly against Gram-negative and Gram-positive bacteria. Additionally, thyme EO exhibits a more potent effect in enhancing cell viability and antibacterial efficacy compared to rosemary EO. Structural analyses through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FT-IR) spectroscopy confirm the successful synthesis of well-integrated HAp-ZnO structures with the EOs. This study offers promising insights into the potential of functionalized nanocomposites for biomedical applications, especially in bone regeneration and infection prevention.