Controllable Biosynthesis of Small Silver Nanoparticles Using Fungal Extract

The search for reliable and eco-friendly methods for the production of nanoscale materials is an important aspect of nanotechnology. Silver nanoparticles (AgNPs) are of special interest because of their antimicrobial properties, especially those of small size. In this work, AgNPs were produced under different conditions of temperature and pH using the extract from the fungus Neurospora crassa as reducing agent. Mainly quasi-spherical particles were obtained at all incubation conditions. However, optimum conditions to produce small sizes in the range of 2 - 9 nm were at 4°C and pH 3, also particles of 2 - 22 nm were obtained at 25°C with unmodified pH (6.5) and pH 10. Nevertheless, only particles synthesized at 25°C and pH 10 maintained the same size range after storage of 10 months. In summary, optimal incubation conditions for the synthesis of silver nanoparticles of small size range are reported. This improves the storage time of particles without losing its original size and without going into aggregation or agglomeration.