Bio-Synthesis of Aspergillus terreus Mediated Gold Nanoparticle: Antimicrobial, Antioxidant, Antifungal and In Vitro Cytotoxicity Studies

Abstract

Gold nanoparticles (GNP) were bio-fabricated utilizing the methanolic extract of the endophytic isolate Aspergillus terreus. The biosynthesised gold nanoparticles (GNP023) were characterised using UV-visible spectroscopy (UV-Vis); transmission electron microscopy (TEM), Fourier-transform nfrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. The bio-fabricated GNP023 displayed a sharp SPR peak at 536 nm, were spherically shaped, and had an average size between 10–16 nm. The EDX profile confirmed the presence of gold (Au), and XRD analysis confirmed the crystalline nature of GNP023. The antimicrobial activity of GNP023 was investigated against several food-borne and phytopathogens, using in vitro antibacterial and antifungal assays. The maximum zone of inhibition was observed for S. aureus and V. cholera at 400 μg /mL, whereas inhibition in radial mycelial growth was observed against Fusarium oxysporum and Rhizoctonia solani at 52.5% and 65.46%, respectively, when challenged with GNP023 (200 μg/mL). Moreover, the gold nanoparticles displayed significant antioxidant activity against the ABTS radical, with an IC50 of 38.61 µg/mL, and were non-toxic when tested against human kidney embryonic 293 (HEK293) cells. Thus, the current work supports the application of myco-synthesised gold nanoparticles as a versatile antimicrobial candidate against food-borne pathogens.

Sustainable Utilization of Food Biowaste (Papaya Peel) Extract for Gold Nanoparticle Biosynthesis and Investigation of Its Multi-Functional Potentials

“…This result is similar to that of an earlier article [66]. The EDS profile of VPPE-AuNPs showed a strong signal for the presence of Au atoms and the sharp absorption peaks between 1-3 keV signify the existence of the Au particles (Figure 1C), which corroborates earlier reports [63,66]. Additionally, the occurrence of C, N, and O in the EDS spectra of VPPE-AuNPs could be due to the VPP extract used in the biosynthesis of VPPE-AuNPs.…”

“…Next, the test reaction was also subjected to spectral analysis using a spectrophotometer at regular time intervals from 0 to 24 h (Figure 1A). The VPPE-AuNPs' reaction kinetics was examined by UV-Vis spectral analysis from 300-700 nm and it displayed a maximum absorption at 552 nm (surface plasmon resonance, SPR) (Figure 1A), which is similar to earlier published reports [62,63]. As specified in earlier studies [62,63], AuNPs characteristically demonstrated just a single SPR band from 500-560 nm, and similar results were also reported here.…”

“…The VPPE-AuNPs' reaction kinetics was examined by UV-Vis spectral analysis from 300-700 nm and it displayed a maximum absorption at 552 nm (surface plasmon resonance, SPR) (Figure 1A), which is similar to earlier published reports [62,63]. As specified in earlier studies [62,63], AuNPs characteristically demonstrated just a single SPR band from 500-560 nm, and similar results were also reported here. The change in color of the VPPE-AuNPs was due to the excitation of SPR of the AuNPs as evident from previous publications [64].…”

“…The Bragg's reflections attained from the synthesized VPPE-AuNPs evidently correspond to the face-centered cubic (fcc) crystalline structure of Au. [63]. The average crystallite size as per the Scherrer equation was calculated as 44.41 nm [69].…”

“…Five individual diffraction peaks ((111), ( 200), ( 220), (311), and (222)) were observed at 2θ = 38.31, 44.60, 64.80, 77.88, and 81.97 of a gold metal (JCPDS card no. 04-0783), showing the existence of pure crystalline gold [63]. The average crystallite size as per the Scherrer equation was calculated as 44.41 nm [69].…”