Green biosynthesis of gold nanometre scale plates using the leaf extracts from an indigenous Australian plant Eucalyptus macrocarpa

In this preliminary study, we demonstrate an environmentally friendly process for the green synthesis of gold nanometre scale particles using the leaf extract from an indigenous Australian plant Eucalyptus macrocarpa as both the stabilising agent and the reducing agent. The synthesis process is straightforward, clean and non-toxic. It also has the advantages of being performed at room temperature and does not need complex processing equipment. Formation of the gold nanometre sized particles was confirmed and characterised by UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. The antibacterial activity of the synthesised gold particles was also quantified using the sensitivity method of Kirby–Bauer.