Biosynthesis of Silver Nanoparticles from Reynoutria bohemica by Hot and Cold Route

Abstract

The purpose of this work was to prepare silver nanoparticles from weedy plant material. The extracts were prepared from fresh and dried Reynoutria leaves at 100 °C, and from dried leaves at 21 °C. Organic substances (e.g. flavonoids) in the extract of Reynoutria bohemica served as reducing agent in the preparation of Ag0 nanoparticles from AgNO3 precursor. Silver nanoparticles were prepared by adding 1 mM AgNO3 and tempered at 70 °C for 24 h. The color change during the formation of the nanoparticles was monitored using UV-vis spectra, where the maximum absorbance was detected at 420 nm. The size and stability of the particles were determined by Dynamic Light Scattering method to 40–50 nm, and their zeta potential was about − 23 mV. Finally, the cold route of biosynthesis appears to be a new and energetically beneficial way for preparing silver nanoparticles. The extracts were prepared from dried leaves at laboratory temperature and AgNPs were also synthesized at laboratory temperature by adding 1 mM AgNO3. The shift of absorption maximum to 450 nm was observed, with a particle size of 85 nm and zeta potential – 24 mV. The preparation was time-consuming (72 h), but without energy costs and utilizing an invasive plant - that is, a truly green synthesis of nanoparticles. This paper introduces a novel approach using the widely distributed invasive plant Reynoutria bohemica for the biosynthesis of silver nanoparticles, developing a cost-effective and energy-saving method that operates at room temperature without heating. Graphical Abstract