In Vivo Biosynthesis of Au and Ag NPs Using Two Medicago sativa L. Genotypes

Abstract

The nano size as well as physical and chemical properties of Au and Ag nanoparticles (NPs) allow them to be used in medicine or plant protection, but chemical solvents used during synthesis makes them toxic and pose a threat to the environment. Chemical NP synthesis can be replaced by in vivo synthesis in which independently growing plants such as alfalfa take up and then split the precursor in their cells down to nano size using synthesis-promoting solvent-biomolecules, which can break down materials without free radicals and have anti-inflammatory, antioxidant effects, making NPs environmentally benign. In this study, two-week-old seedlings of two Medicago sativa L. genotypes, ‘Kometa’ and ‘la Bella’, were exposed to two precursors (AgNO3, HAuCl4) for 24 and 48 h to determine whether in vivo synthesis is possible. Two-beam and certain wavelength spectrophotometry and confocal microscopy confirmed statistically significant (p < 0.05) changes in light absorption and light fluorescence compared to the control. Confocal microscopy showed both precursors visible in the roots of both genotypes. Currently, NP synthesis and visualisation methods require a complex, expensive, and time-consuming sequence of methods. It is important to find an effective, environmentally friendly, and as cheap and simple as possible method for the biosynthesis of NPs.