Green synthesis of gold nanoparticles using aqueous leaf extract of Populus alba: characterization, antibacterial and dye degradation activity

Gold nanoparticles have found their application as optical probes, antibacterial agents, catalyst and sensors. Here, we report the synthesis of gold nanoparticles (GNPs) using leaf extract (LE) of three different plants viz., Populus alba (PA), Lantana camara (LC) and Hibiscus arboreus (HA). The effect of reaction temperature and concentration of leaf extracts (LEs) were studied in detail on the synthesis and size of GNPs. The prepared GNPs were chemically characterized by UV–Vis and FTIR whereas the morphological analysis was done using DLS, TEM and SEM. When 5% PA LE was used at 65 °C, almost uniform shaped GNPs were obtained of size ~ 16.3 ± 0.7 nm. The as prepared GNPs showed antibacterial activity against both Staphylococcus aureus and Escherichia coli with MIC value of ~ 100 µg/ml. Further, these GNPs were also used for the degradation of toxic dyes viz., methylene blue (MB) and congo red (CR). Overall, present studies suggested the use of green synthesized GNPs in both biomedical and analytical field.