Ali Mohammadian - Department of biotechnology, Faculty of Science, University of Tehran, Tehran, Iran.
Seyed Abbas Shojaosadati - Biotechnology Group, Faculty of Engineering, Tarbiat Modares University, Tehran, Iran.
Sayyed Mehran Habibi Rezaee - Department of biotechnology, Faculty of Science, University of Tehran, Tehran, Iran.
Sayyed Mohammad Hashemi Dogaheh - Faculty of Science, University of Tehran, Tehran, Iran.

In the present report, the first combinatorial approach to the green synthesis of metallic nanoparticles using living organisms is presented. Fungus Fusarium oxysporum cultured on Vogel's medium, , secrets species into the culture broth that can reduce silver ions and hinder clusters of silver atoms from agglomeration, so producing silver nanoparticles. The rapid photoreduction of silver ions in the culture broth in presence of daylight and even weak conventional lamps, and ambient conditions (T = 20 °C) was observed, with highly stable silver nanoparticles formed within just 35 minutes of reaction under a conventional tungsten-halogen lamp. This synthesis was monitored by UV-vis spectroscopy, and scanning (SEM) and transmission electron microscopy (TEM) along with Energy dispersive spectroscopy (EDS) analyses was used to analyze the nanoparticles and it was verified that the particles were indeed sub-micrometric metallic silver. The nanoparticle solutions show no degree of agglomeration (as evidenced by color of the solution) even after 3 months of production and can be centrifuged and re-dispersed in water. The nanoparticles, as demonstrated by UV-vis peak width ,are not more poly-dispersed than those obtained in 72 hours by purely biological methods .This work shows that combinatorial methods would enhance micro-organismal based nanoparticle synthesis .

Silver nanoparticle, Light sensitivity, Fusarium oxysporum, Extracellular