Green Synthesis and Characterization of SiO

Silica nanoparticles (SiO₂ NPs) are versatile nanomaterials with tunable physicochemical properties and excellent biocompatibility, making them suitable for biomedical applications. In this study, a green synthesis approach was employed using Origanum majorana leaf extract as a natural reducing and stabilizing agent to fabricate biofunctionalized SiO₂ nanoparticles. The novelty of this work lies in utilizing a phytochemically rich yet underexplored plant source for synthesizing silica nanoparticles and systematically evaluating their multifunctional biological properties. The synthesized nanoparticles were characterized using UV-Vis spectroscopy, FTIR, XRD, FESEM, EDX, and DLS analyses, confirming the formation of amorphous, high-purity SiO₂ nanoparticles with Si-O-Si and Si-OH functional groups. FESEM analysis revealed particle sizes of 50-200 nm, while DLS indicated a hydrodynamic diameter of 298.3 nm (PDI = 0.496). The nanoparticles exhibited significant antioxidant activity (96.7% DPPH scavenging at 10 µg/mL), concentration-dependent antimicrobial effects, notable anti-inflammatory activity (IC₅₀ = 165 µL), and moderate cytotoxicity against L929 fibroblast cells (IC₅₀ = 112.06 µg/mL). This study presents an eco-friendly strategy for producing biofunctionalized silica nanoparticles with promising applications in nanomedicine and antimicrobial therapy.