Multifunctional properties of spherical silver nanoparticles fabricated by different microbial taxa

Sultan M Alsharif; Salem S Salem; Mohamed Ali Abdel-Rahman; Amr Fouda; Ahmed Mohamed Eid; Saad El-Din Hassan; Mohamed A Awad; Asem A Mohamed

doi:10.1016/j.heliyon.2020.e03943

Multifunctional properties of spherical silver nanoparticles fabricated by different microbial taxa

Heliyon. 2020 May 15;6(5):e03943. doi: 10.1016/j.heliyon.2020.e03943. eCollection 2020 May.

Authors

Sultan M Alsharif¹, Salem S Salem², Mohamed Ali Abdel-Rahman², Amr Fouda², Ahmed Mohamed Eid², Saad El-Din Hassan², Mohamed A Awad³, Asem A Mohamed⁴

Affiliations

¹ Biology Department, Faculty of Science, Taibah University, Al Madinah, KSA.
² Botany and Microbiology Department, Faculty of Science, Al-Azhar University, 11884, Nasr City, Cairo, Egypt.
³ Department of Zoology and Entomology, Faculty of Science, Al-Azhar University, 11884, Nasr City, Cairo, Egypt.
⁴ National Research Centre, El-Behouth St., Dokki, P.O. 12622, Giza, Egypt.

Abstract

This study addresses the impacts of metabolites from different microbial taxa on the fabrication and multifunctional biological properties of spherical silver nanoparticles (Ag-NPs). Three microbial taxa, a bacterial (Bacillus cereus A1-5), actinomycetes (Streptomyces noursei H1-1), and fungal (Rhizopus stolonifer A6-2) strains were used for Ag-NPs biosynthesis, whereas Streptomyces noursei is demonstrated for the first time. These isolates were identified using either 16S rRNA or ITS gene sequencing. Characterization of Ag-NPs was done using color change analysis, Uv-Vis spectroscopy, FT-IR spectroscopy, XRD, TEM, SEM-EDX, DLS, and Zeta potential analysis. All biosynthesized NPs exhibited spherical shape with different sizes ranged from 6‒50 nm, 6-30 nm and 6-40 nm for NPs obtained by A1-5, H1-1 and A6-2, respectively. The crystalline center cubic face of Ag-NPs was confirmed using XRD at 2θ values 38.08^o, 44.27^o, 64.41^o and 77.36^o. FT-IR analysis revealed varied intense absorption peaks for biomolecules required for NPs synthesize by each microbial strain. The stability of spherical Ag-NPs was confirmed due to highly DLS negative surface charge of ‒17.5mV, ‒18.9mV, and ‒15.6mV for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Ag-NPs exhibited a broadspectrum of antibacterial activity against Gram-positive and Gram-negative bacteria with varied effectiveness. They also exhibited a cytotoxic effect against cancer cell line (caco-2) in a dose-dependent pattern with IC50 of 8.9 ± 0.5, 5.6 ± 3.0, 11.2 ± 0.5 μg/ml for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Moreover, these spherical Ag-NPs showed larvicidal activity against the 3^rd instar larvae of the dengue vector Aedes aegypti.

Keywords: Aedes aegypti; Ag-NPs biosynthesis; Agriculture; Antibacterial; Antitumor activities; Larvicidal; Materials science; Nanotechnology; Spherical silver nanoparticles.