Roots of Pennisetum sp. possess the competence to generate nanoparticles of noble metals

Abstract

Roots of plants have immense reducing potential. Ions of noble metals namely Au3+ and Ag+ get reduced easily to form Au and Ag nanoparticles (NPs), respectively. Therefore, we hypothesize that plant roots could have potential to form Au-NPs and Ag-NPs. For present investigations, plants of Pennisetum glaucum L. were used to evaluate if their roots possess capacity to generate metal NPs. The generation of Au-NPs and Ag-NPs was initially presumed based on colour change, and confirmed by UV-vis spectra, TEM and EDX investigations. Pale yellow Au3+ and colourless Ag+ solutions turned purple and brown, respectively, by roots of Pennisetum sp. within 8 h. Absorption spectra of respective solutions showed plasmon resonance band at 560 nm and 420 nm confirming the presence of Au-NPs and Ag-NPs. TEM coupled with SAED revealed the presence of crystalline spherical NPs in the size range of 5-50 nm in these solutions. EDX further confirmed the presence of Au and Ag as NPs of respective solutions. These results confirmed that the roots of P. glaucum possess ideal reducing strength to generate Au-NPs and Ag-NPs exogenously in the aqueous phase.