Antibacterial mechanism of biogenic copper nanoparticles synthesized using Heliconia psittacorum leaf extract

Here, we report on the novel green synthesis of metallic copper nanoparticles from copper sulfate solution by using the leaf extract of Heliconia psittacorum. The stability and gradual formation of copper nanoparticles during interaction with the extract were investigated using ultraviolet-visible spectroscopy. The pattern of X-ray diffraction revealed the crystallinity and different phases of the nanoparticles. High-resolution transmission electron microscopy was done to obtain information about the morphology and microstructure of the green nanoparticles. The infrared spectra detected organic bioactive molecules associated with capping and stabilization of the particle surface. The antibacterial properties of these bioengineered Cu nanoparticles were tested toward a Gram-positive bacteria - Staphylococcus aureus - and two strains of Gram-negative bacteria - Escherichia coli and Pseudomonas putida. The antibacterial study showed that these biogenic copper nanoparticles have potent bactericidal property toward the examined bacterial species.