Biosynthesis and Biosensing Applications of Silver and Gold Metal Nanoparticles

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. Molecular 18srRNA techniques identified the two fungal strains as Aspergillus terreus MM1-EGY and Aspergillus flavus MM2-EGY isolate, respectively. The biosynthesized silver nanoparticles by Aspergillus terreus isolate MM1-EGY exhibited UV absorbance around 420 nm with particle size ranging from 15 to 35 nm. Gold nanoparticles biosynthesized using Aspergillus flavus isolate MM2-EGY showed an absorption maximum at 550 nm with particle size ranging from 20 to 50 nm. The biosynthesized AuNPs were preliminary tested for 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.