Biosynthesis of silver nanoparticles using Bougainvillea flower extract: Antibacterial, antibiofilm and cytotoxicity studies

This study investigated a sustainable approach for synthesizing silver nanoparticles (AgNPs) utilizing an extract from the flower of Bougainvillea glabra plant. The successful synthesis of AgNPs was confirmed by various biophysical techniques: UV–Vis spectroscopy revealed a prominent peak (432 nm), whilst FT-IR and XRD investigations confirmed their chemical composition and crystalline structure. TEM investigations indicated that the AgNPs measured around an average of 25.05 ± 0.87 nm and exhibited a spherical morphology. MIC values against gram-positive and gram-negative ranged from 32 to 128 μg/mL. The XTT assay shows that AgNPs at 500 μg/mL proficiently inhibits bacterial biofilm by 96 %. Light and electron microscopy investigations have indicated that AgNPs dramatically restrict their colonization and adhesion. SEM and TEM show that the cell surface exhibited irregularities, roughness, distortion, and an impaired state, characterized by a defective cellular membrane and its wall, signifying an impairment of membrane integrity that subsequently leads to cell death. Furthermore, the AgNPs exhibited a regulated toxic effect on breast cancer cells, inducing apoptosis while maintaining biocompatibility and sparing healthy cells. The promising results suggest that this eco-friendly way of making AgNPs could lead to new methods for delivering drugs to fight cancer and treat infections associated to biofilms.