Study of the green synthesis of silver nanoparticles using a natural extract of dark or white Salvia hispanica L. seeds and their antibacterial application

In this research work, we report for the first time the green synthesis of silver nanoparticles (AgNPs), using two varieties of a natural extract of dark (D) or white (Wh) Salvia hispanica L. seeds, commonly named chia (Ch), as a reducing-stabilizing agent. Similarly, it was carried out a study on the effect of the variation of different physicochemical parameters, like aging time and storage temperature of the natural extract of dark Ch seeds, in the morphology, size and polydispersity of the prepared AgNPs. We found that the ideal conditions to do the green synthesis of AgNPs, are to use the Ch extract one day after it have been prepared and stored at 5 °C (1D C). The AgNPs were characterized by UV–Vis, FT-IR, FE-SEM-EDS and TEM. The TEM images of the synthesized AgNPs showed spherical morphology with an average nanoparticle size of 7 nm, at optimum conditions (AgNPs/D Ch (1D C)). Additionally, we studied the antimicrobial activity of the green synthesized AgNPs with both types of Ch seeds, against bacteria gram-positive and gram-negative, using as the bacterial model E. coli and S. aureus, respectively. We determined that the synthesized AgNPs/D Ch have more antimicrobial activity against both bacteria, in comparation with AgNPs/W Ch (ZOI against E. coli, 18.5 mm; S. aureus, 14.9 mm).