Rapid mediated biosynthesis and quantification of AuNPs using persimmon (Diospyros Kaki L.f) fruit extract

Abstract

Persimmon (Diospyros Kaki L.f), as a common fruit, is rich in polyphenols, flavonoids and sugars, having high ability for synthesis of nanoparticles. Thus, biosynthesis of AuNPs using persimmon fruit extract was investigated in this study. The results of UV–visible spectra, transmission electron microscopy images and dynamic light scattering demonstrated that the size and shape of AuNPs highly depended on the concentration of HAuCl4·4H2O and reaction temperature. When 1.0 and 1.5 mM of HAuCl4·4H2O were used as precursors, triangular and hexagonal AuNPs were formed; furthermore, 2.0 mM of HAuCl4·4H2O induced the formation of nanoaggregates. Although higher temperatures (e.g., 50, 60 and 70 °C) boosted the isotropic growth of AuNPs, they had no expressive impact on AuNPs size. Centrifugal ultrafiltration method with inductively coupled plasma-mass spectrometry was applied to assess the transformation efficiency of Au3+ during this biosynthesis procedure. So, the results indicated that more than 97% of Au3+ ions were successfully converted into AuNPs. In addition, the XRD analysis confirmed that AuNPs had face-centered cubic structure. Fourier transform infrared spectroscopy revealed that different functional groups (especially hydroxyl group) were mainly involved in the fabrication of AuNPs. The biosynthesized AuNPs exhibited good antioxidant and catalytic activities.