Plant extracts interact with metal ions and reduce them to metallic nanoparticles. This interaction is given in Figure 1. Biomolecules present in Lamium Galeobdolon extract are responsible for the reduction of Ag+ ions to Ag0. As Ag+ ion source, 0.1 molar silver nitrate (AgNO3) was used.
Biological reduction of Ag+ ions
For the synthesis of silver nanoparticles, 150 ml of plant extract and 300 ml of distilled water were put into a beaker and the was stirred with a magnetic stirrer. During the process, 50 ml of 0.1 molar AgNO3 solution was added dropwise to the solution. After mixing, the solution was kept in the dark to prevent photochemical reactions. The formation of silver nanoparticles was also confirmed using UV-vis. In the study, a color change from yellow to dark was observed in the solution. The color change from yellow to dark is an indicator of the synthesis of AgNPs. Then, the pure water in the solution was evaporated at 200°C in an oven. As a result of this process, silver nanoparticles encapsulated with Lamium Galeobdolon extract were obtained. The processes for the green synthesis of encapsulated silver nanoparticles are shown in Figure 2.
Schematic representation of the steps to obtain encapsulated silver by green synthesis
