Synthesis and Characterization of Silver Nanoparticles Prepared With Aqueous Extract of Coriander (coriandrum Sativum) and Coated With Dragon’s Blood Latex (croton Lechleri)

Abstract

The aim of this study was to synthesize and characterize silver nanoparticles by means of Green Chemistry methods; plant extracts were used in the procedure. First, silver nanoparticles were synthesized with 10 mM AgNO₃ and a coriander aqueous extract 5 %. Later, latex obtained from dragon’s blood 10 % in ethanol-water (1:1), was spiked to the preparation mixture. Silver nanoparticle formation was established with UV-visible spectroscopy by means of measurements at 422 and 439 nm, before and after latex addition, respectively. Characterization was performed by Fourier transform Infrared Spectrophotometry with Horizontal Attenuated Total Reflectance accessory (FTIR-HATR), Scanning Electron Microscopy coupled to X-ray (SEM-EDX), Flame Atomic Absorption Spectrophotometry (FAAS) and, Dynamic Light Scattering (DLS). Changes in FTIR spectra bands were evident when comparing nanoparticles obtained with the initial extract and with the colloidal dissolution (latex). Nanoparticle size was determined using SEM; an average value of 50 nm and 72 nm was obtained at each stage. EDX analysis showed the presence of silver: 14.9 % in the product of the synthesis and 0.6 % after adding latex, suggesting the formation of an organic coating around the nanoparticles. However, silver concentration, estimated with FAAS, did not show differences between nanoparticles with and without dragon’s blood. Besides, nanoparticle hydrodynamic size was found by means of DLS, being the ones without cover, those with a higher value (294.3 vs. 259.0 nm). Finally, it was concluded that the methodology used for this synthesis was successful, and it allows silver nanoparticles coating with other plant extracts, thus improving its applicability in biomedical and microbiological investigations.