Plant extract-based biosynthesis of silver nanoparticle and silver–zinc nanocomposites-doped hydroxyapatite and its antimicrobial activity

Hydroxyapatite (HAp) is an essential material in the biomedical field because of its chemical composition, similar to the apatites found in bones. The lack of bactericidal properties of HAp-based materials cannot prevent the adhesion and growth of bacteria. However, it can develop composite biomaterials using nanoparticles (NPs) such as silver (Ag) and zinc (Zn), which exhibit biocidal behaviours to control resistant microorganisms. This study aimed to prepareHAp–AgNPs and HAp–Ag@ZnNPs nanocomposite and evaluate their antimicrobial properties against Gram-positive and Gram-negative bacteria. HAp powders were produced from sheep bone. An aqueous extract of Marrubium astracanicum was used as a reducing and stabilising agent for the synthesis of NPs. The composites were characterized by XRD, SEM–EDX, SEM and FTIR. In vitro biocompatibility assessment was determined by agar well diffusion tests. The HAp–Ag@ZnNPs nanocomposites showed stronger antimicrobial activity than HAp–AgNPs against bacteria and fungi, while pure HAp did not show any effect.