Biosynthesis of SERS active silver nanostructures using Anemopsis californica extract

Silver nanoparticles (AgNPs) have many potential applications; therefore, biological methods for synthesis have been widely explored to use an eco-friendly protocol. Here we report the synthesis of AgNPs with extract of Anemopsis californica and determined the effect of the solvent employed to obtain the extract (water, methanol, and isopropanol). Formation of nanoparticles was analyzed by UV–Vis spectroscopy and transmission electron microscopy. Significant differences in polydispersity and morphology of AgNPs were found; aqueous extract produced nanostructures such as flowers, icosahedrons, rods and inukshuks; predominant size of AgNPs was 70.5 ± 20.7 nm. When using methanol and isopropanol as solvents, predominant shape were spheroids with average sizes of 21.8 ± 10.8 nm and 27.8 ± 10.6 nm, respectively. The NPs were supported on glass slides and were used to realize Surface-Enhanced Raman Scattering. Different Raman signals of amplification of methylene blue was obtained depending on the laser, better results were obtained with the nanoparticles synthesized using aqueous and isopropanol extracts. Graphical abstract