Synthesis and Characterization of Silver Nanoparticles Using Alginate from the Brown Seaweed Laminaria ochroleuca: Structural Features and Antibacterial Activity

Abstract

In this study, inexpensive and eco-friendly production of the silver nanoparticles (AgNPs) was explored using Laminaria ochroleuca sodium alginate as stabilizing and reducing agent. The synthesized nanoparticles were characterized by various analytical techniques such as UV–Vis spectroscopy, Energy dispersive X-ray spectrometer (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), TEM selected area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The synthesis of AgNPs was elucidated by characteristic absorption peaks in the UV–Vis test. The FTIR analysis revealed the involvement of many functional groups in the bioreduction and the stabilization of AgNPs, while TEM images illustrated the spherical shape with maximum particles found in the size range of 10-20 nm. Prominent peaks and silver diffraction rings shown by the XRD spectrum and SAED pattern, respectively, confirmed the crystalline nature (fcc) of the synthesized AgNPs, which were found to be thermally stable based on TGA analysis. The AgNPs exhibited strong antibacterial activity against Gram+ and Gram– bacteria. The synthesized silver nanoparticles using Laminaria ochroleuca sodium alginate revealed interesting properties that could be potentially used for pharmaceutical applications.