Biogenic synthesis of antioxidant, shape selective gold nanomaterials mediated by high altitude lichens

Biogenic synthesis of gold nanoparticles have been accomplished using dried biomass of two high altitude lichen species, collected from the alpine region of Eastern Himalaya in Arunachal Pradesh state of North East India, without addition of any external reducing or stabilizing chemicals. The nanoparticles were characterised by UV–visible, FT-IR spectroscopy, powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-obtained gold nanoparticles showed surface plasmon resonance (SPR) band at ~535 nm. The XRD study furnished evidence for the formation of face-centered cubic structure of gold nanomaterials. The nanoparticles produced with Acroscyphus sp. consisted of multiply twinned quasi-spherical and prismatic shapes while those accessed with Sticta sp. are exclusively multiply twinned. The biomatrix loaded gold nanomaterial exhibited pronounced antioxidant activity.