Plant mediated greener approach for synthesis of silver nanoparticles from Digitalis purpurea plant and its antibacterial activity

In this paper, silver nanoparticles were biosynthesised using aqueous Digitalis purpurea leaf extract. The biosynthesised silver nanoparticles were characterised by UV-visible (UV-vis) spectrophotometer, Fourier transform infrared spectroscopy (FTIR), x-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX) analysis and high-resolution transmission electron microscopy (HRTEM). In the colloidal solution, the formation and stability of the silver nanoparticles were identified by UV-visible and it showed the maximum absorption at 452 nm. XRD and HRTEM analysis showed that the silver nanoparticles were cubic structured, face centred with a particle size of 25 nm and EDX evidenced the presence of silver element. The FTIR analysis revealed the existence of various functional groups. Antibacterial activity of the synthesised silver nanoparticles was evaluated against the gram-negative Escherichia coli (MTCC 1652) and gram-positive Staphylococcus aureus (MTCC 316) bacteria, showed the efficient activity against both the gram-negative and gram-positive microorganisms.