Microwave-assisted synthesis of silver nanoparticles using sodium alginate and their antibacterial activity

A simple, green, microwave-assisted method of synthesizing silver nanoparticles was developed using sodium alginate as stabilizer and reducer. A possible mechanism involved in the reduction and stabilization of nanoparticles was investigated. The effect of reaction conditions such as the concentration of sodium alginate and AgNO3, irradiation time and pH on the synthesis of silver nanoparticle was studied. The silver nanoparticles were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD). The results indicated the formation of spherical, nanometer-sized particles. The reaction parameters significantly affected the formation rate, size and distribution of the silver nanoparticles. XRD analysis revealed that the particles were face-centered cubic. The silver nanoparticles prepared in this way were uniform and stable, which could be stored at room temperature for at least 6 months. The synthesized silver nanoparticles had significant antibacterial activity on two kinds of Gram bacteria.