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Biosynthesis of gold nanoparticles by two bacterial and fungal strains, Bacillus cereus and Fusarium oxysporum , and assessment and comparison of their nanotoxicity in vitro by direct and indirect assays
Pourali, Parastoo; Badiee, Seyyed Hossein; Manafi, Sahebali; Noorani, Tahereh; Rezaei, Azadeh & Yahyaei, Behrooz
Abstract
Background: Although nanoparticles (NPs) have many advantages, it has been proved that they may be absorbed
by and have toxic effects on the human body. Recent research has tried to evaluate and compare the nanotoxicity
of gold nanoparticles (AuNPs) produced by two types of microorganisms in vitro by two different methods.
AuNPs were produced by Bacillus cereus and Fusarium oxysporum, and their production was confirmed by
visible spectral, transmission electron microscope, and X-ray diffraction (XRD) analyses. The human fibroblast
cell line CIRC-HLF was treated with AuNPs, and the induced nanotoxicity was measured using direct
microscopic and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays.
Results: The results showed that the produced AuNPs had a maximum absorbance peak around 510–530
nanometer (nm), with spherical, hexagonal, and octagonal shapes and average sizes around 20–50 nm. The
XRD results confirmed the presence of GNPs in the microbial culture supernatants. An MTT assay showed that
GNPs had dose-dependent toxic effects, and microscopic analysis showed that GNPs induced cell abnormalities
in doses lower than the determined half-maximal inhibitory concentrations (IC50s).
Conclusions: In conclusion, the biologically produced AuNPs had toxic effects in the cell culture, and direct
techniques such as microscopic evaluation instead of indirect methods such as MTT assay were more useful for
assessing the nanotoxicity of the biologically produced AuNPs. Thus, the use of only MTT assay for nanotoxicity
evaluation of AuNPs is not desirable.
Keywords
Biologically produced nanoparticles; Drug delivery; In vitro nanotoxicity; In vivo nanotoxicity; Nanoparticle production; Nanotechnology; Nanotoxicity analysis; Purification of nanoparticles; Surface plasmon resonance; Visible spectral analysis; X-ray diffraction analysis
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