Spectroscopy study of silver nanoparticles fabrication using synthetic humic substances and their antimicrobial activity.

In this present study, silver nanoparticles were synthesized using synthetic humic substances (HSs) as reducing and stabilizing agents. Preference of synthetic HSs over natural humic matter is determined by a standardization problem resolution of the product due to the strict control of conditions of the synthetic HSs formation. It allows to receive the silver nanoparticles with the standardized biologically-active protective shell that is very important for their use, mainly in medicine. The concentration of sodium hydroxide, synthetic HSs, silver nitrate and temperature employed in the synthesis process are optimized to attain better yield, controlled size and stability by means of UV-visible technique. In the optimal reaction conditions the concentrated silver colloids (55 mM) with 99.99% yield are obtained which were stable for more than 1 year under ambient conditions. The received silver nanoparticles are characterized by UV-visible spectroscopy, X-ray diffraction (XRD), FT-IR spectroscopy and transmission electron microscopy (TEM). The antimicrobial activity of silver nanoparticles against fungal and bacterial strains is also shown.