Biogenic synthesis of silver nanoparticles from thyme extract for functionalization of a bioactive glass produced from rice husk ash

Abstract

The rice husk, agro-industrial residue, stands out for having silica, the main oxide former of the bioactive glass. To avoid contamination in this biomaterial, substances with bactericidal properties, like silver can be incorporated. Thus, the objective of this work is the synthesis of silver nanoparticles to functionalize a bioactive glass synthesized from rice husk ash (BRHA). The bioglass was prepared by the sol-gel method from the rice husk ash as a silica source. Silver nanoparticles were synthesized from thyme extract with AgNO3 and their formation was verified by UV-vis spectroscopy. The glass powder was added to this solution and its structure was evaluated by SEM-EDS, ATR-FTIR, and microbiology. The bioglass powder appeared in the form of porous agglomerates and the addition of silver altered its superficial roughness by deposition. The chemical bonds of the glass network related to bioactivity were maintained after the incorporation of the nanoparticles. Microbiological analysis by the agar diffusion test confirmed the inhibitory action of the nanoparticles for P. aeruginosa and S. aureus. Therefore, the developed material presented great potential for biomedical applications.