Plasma-chemical formation of silver nanoparticles: the silver ions concentration effect on the particle size and their antimicrobial properties

Silver nanoparticles (AgNPs) are prepared by plasma-chemical discharge irradiation of silver nitrate solution without using reducing or capping agents. The nanoparticles are characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) absorption spectroscopy. The effect of the silver ions concentration on the size of the silver particles is studied. The optical absorption spectroscopy of AgNPs prepared at different silver ions concentrations shows a surface plasmon resonance at ca 395 nm - 440 nm. Spherical, nanometer-sized particles are obtained. The average particle size is observed to increase with the initial AgNO₃ concentration increase. Highly monodispersed silver nanoparticles are obtained within 5 min of plasma irradiation. XRD analysis reveals that the particles are face-centred cubic one. The synthesized silver nanoparticles have a significant antibacterial activity on two strains of Gram bacteria.Keywords: silver nanoparticles, ions concentrations, average diameters, antibacterial activity.