Green Synthesis of Silver Nanoparticles using Coffea canephora L. Leaves Aqueous Extract with its Antioxidant Activity and H2O2 Sensor Ability

Green synthesis provides a sustainable approach for nanoparticle production by minimizing toxic reagents and environmental impact. Given the increasing demand for eco-friendly nanomaterials with biomedical and environmental relevance, this study aimed to synthesize and characterize silver nanoparticles (AgNPs) using aqueous extracts of Coffea canephora L. leaves, which are rich in antioxidant compounds serving as natural reducing agents. The biosynthesized AgNPs exhibited a localized surface plasmon resonance (LSPR) peak at 438 nm, while SEM analysis revealed irregular morphologies with an average particle size of ~70 nm. Dynamic light scattering confirmed a Z-average of 70.16 nm and a low polydispersity index (0.244), indicating high dispersion stability. Compared to the crude leaf extract, the AgNPs showed significantly enhanced antioxidant potential, with stronger DPPH radical scavenging activity (IC₅₀ = 51.94 ± 0.59 mg/L vs. 85.29 ± 3.67 mg/L). Moreover, the AgNPs demonstrated excellent sensing capability toward H₂O₂, achieving detection limits as low as 0.0068 mM and 0.0575 mM. These results suggest that Coffea canephora L. mediated AgNPs not only provide an eco-friendly route for nanoparticle synthesis but also hold strong potential for biomedical, biosensing, and active food packaging applications.