Hybrid chemical-biogenic synthesis of silver nanoparticles with antibacterial efficacy using Salicornia and Sarcocornia hydroethanolic extracts

Abstract

This study investigates the use of a hybrid approach combining various ratios of sodium borohydride (NaBH4) with hydroethanolic extracts of Salicornia emerici, Sarcocornia fruticosa, and Sarcocornia alpini as reducing agents for AgNPs synthesis. The resulting nanoparticles were confirmed by the presence of a characteristic absorption peak around 400 nm using UV-visible spectroscopy, observed for Sarcocornia-mediated AgNPs at a 1:5 (v/v) extract-to-NaBH4 ratio and at a 1:2 (v/v) ratio for AgNPs synthesized from S. emerici (SE-AgNPs). Furthermore, their size, dispersity and morphology were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM), respectively. The nanoparticles displayed variable sizes with broad polydispersity, reflecting heterogeneous nucleation associated with plant-derived metabolites, and predominantly exhibited a cubic shape. Their antibacterial activity against different bacterial strains was evaluated using the broth microdilution method. All formulations inhibited bacterial growth, showing size-independent efficacy. The inhibition of multidrug-resistant bacteria Enterococcus faecalis was particularly noteworthy, with the strongest efficacy observed in SE-AgNPs at a concentration of 21.9 µg/mL. Taken together, the findings suggest that hybrid synthesis can generate bioactive AgNPs while partially reducing dependence on strong chemical reductants. Future work should focus on improving nanoparticle size control, cytotoxicity assessment, and elucidating the mechanistic pathways underlying their bioactivity.