Biosynthesis and Bio-sensing Applications of Silver and Gold Metal Nanoparticles

Abstract

Biogenic nanoparticles have gained major interest because of their eco-friendly approach, as non-toxic chemicals are involved in the biosynthesis, and the preparation process carried out at ambient pressure and temperature. In the present study, two fungal strains (MM1and MM2) showed the ability to biosynthesize silver and gold nanoparticles, respectively, were isolated from local Egyptian soil samples. These two fungi were identified by the molecular technique 18srRNA as Aspergillus terreus isolate MM1-EGY and Aspergillus flavus isolate MM2-EGY. The biosynthesized silver nanoparticles by Aspergillus terreus isolate MM1-EGY exhibited UV absorbance around 420 nm and particle size range of 15-35 nm as measured by transmission electron microscopy (TEM). On the other hand, gold nanoparticles biosynthesized by Aspergillus flavus isolate MM2-EGY showed maximum UV/Vis absorbance around 550 nm and size range of 20-50 nm. The XRD of both AgNPs and AuNPS was constructed. The green synthesized gold nanoparticles were tested for sensitive and selective simultaneous voltammetric determination of neurotransmitter metabolite, vanillylmandelic acid (VMA) and homovanillic acids (HVA), while silver nanoparticles were applied for the fabrication of disposable screen-printed Ag/AgCl planner reference electrode.