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. 2019 Sep 10;9(1):13071.
doi: 10.1038/s41598-019-49444-y.

Synthesis and biological characterization of silver nanoparticles derived from the cyanobacterium Oscillatoria limnetica

Ragaa A Hamouda  1   2 , Mervat H Hussein  3 , Rasha A Abo-Elmagd  3 , Salwa S Bawazir  4
Affiliations

Synthesis and biological characterization of silver nanoparticles derived from the cyanobacterium Oscillatoria limnetica

Ragaa A Hamouda et al. Sci Rep. .

Abstract

Using aqueous cyanobacterial extracts in the synthesis of silver nanoparticle is looked as green, ecofriendly, low priced biotechnology that gives advancement over both chemical and physical methods. In the current study, an aqueous extract of Oscillatoria limnetica fresh biomass was used for the green synthesis of Ag-NPs, since O. limnetica extract plays a dual part in both reducing and stabilizing Oscillatoria-silver nanoparticles (O-AgNPs). The UV-Visible absorption spectrum, Fourier transforms infrared (FT-IR), transmission electron microscopy (TEM) and scanning electron microscope (SEM) were achieved for confirming and characterizing the biosynthesized O-AgNPs. TEM images detected the quasi-spherical Ag-NPs shape with diverse size ranged within 3.30-17.97 nm. FT-IR analysis demonstrated the presence of free amino groups in addition to sulfur containing amino acid derivatives acting as stabilizing agents as well as the presence of either sulfur or phosphorus functional groups which possibly attaches silver. In this study, synthesized Ag-NPs exhibited strong antibacterial activity against multidrug-resistant bacteria (Escherichia coli and Bacillus cereus) as well as cytotoxic effects against both human breast (MCF-7) cell line giving IC50 (6.147 µg/ml) and human colon cancer (HCT-116) cell line giving IC50 (5.369 µg/ml). Hemolytic activity of Ag-NPs was investigated and confirmed as being non- toxic to human RBCs in low concentrations.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
UV-visible absorption spectrum of O. limnetica extract & AgNO3 (A) and silver nanoparticles (O-AgNPs) biofabricated after 48 h of reaction (B).
Figure 2
Figure 2
(A) UV-visible absorption spectra of O-AgNPs biosynthesized at various pH values [4.7, 5.7, 6.7, 7.7 and 8.7]. (B) O-AgNPs at various O. limnetica extract content (ml) [1, 2, 3, 4, 5 and 6]. (C) O-AgNPs at various AgNO3 concentrations (mM) [0.1, 0.2, 0.3, 0.4 and 0.5]. (D) UV-Visible spectra of O-AgNPs at different time intervals (h) [6, 12, 18, 24, 36 and 48].
Figure 3
Figure 3
Stability of O-AgNPs.
Figure 4
Figure 4
TEM image of O-AgNPs (A,B), particles size distribution (C) and SEM image of biosynthesized O-AgNPs (D).
Figure 5
Figure 5
FT-IR spectrum of O. limnetica extract and O-AgNPs at different reaction time (h) [6, 12, and 48].
Figure 6
Figure 6
Antibacterial activity (zone of inhibition) of O-AgNPs against two human pathogenic bacteria E. coli (A,C) and B. cereus (B,D) where (1) is AgNO3, (2) O-AgNPs stored, (3) O-AgNPs, (4) is O. limnetica extract, (5) A is Cefaxone-AgNPs & (5) B is tetracycline-AgNPs and (6) A is Cefaxone & (6) B is tetracycline.
Figure 7
Figure 7
Bacterial growth inhibition (culture optical density) of O-AgNPs against E. coli (A) and B. cereus (B).
Figure 8
Figure 8
TEM morphological changes of B. cereus as cell structure with or without O-AgNPs. (a) Structure of intact cell (control), (b) damaged cell membrane and releasing of cytoplasm, (c,d) dark mineral particles and electron dense particles within cytoplasm, (d,f) cellular disintegration and (e,f) shrinking of protoplasm and detachment of cellular membrane (cellular deformation). (g) EDX spectrum of B. cereus cells with O-AgNPs.
Figure 9
Figure 9
Percentage of hemolysis caused by O-AgNPs.
Figure 10
Figure 10
Cytotoxicity of O-AgNPs on human breast cancer cell line (M CF-7) (A) and colon cancer cell line (HCT-116) (B).
Figure 11
Figure 11
Microscopic evaluation of the effect of the O. limnetica extract (A), O-AgNPs (B) as well as the silver nitrate alone (C) in a bright field (top raw) or after staining with crystal violet (lower raw) on MCF-7 cells at concentration of 120 µg/ml.
See this image and copyright information in PMC

References

    1. Bilal M, Rasheed T, Iqbal HMN, Hu H, Zhang X. Silver nanoparticles: Biosynthesis and antimicrobial potentialities. Int. J. Pharmacol. 2017;13:832–845. doi: 10.3923/ijp.2017.832.845. - DOI
    1. Sharma A, et al. Algae as crucial organisms in advancing nanotechnology: a systematic review. J Appl Phycol. 2015;28:1759–1774. doi: 10.1007/s10811-015-0715-1. - DOI
    1. Rittner MN, Abraham T. Nanostructured materials: An overview and commercial analysis. JOM. 1998;50:37–38. doi: 10.1007/s11837-998-0065-4. - DOI
    1. Chaloupka K, Malam Y, Seifalian AM. Nanosilver as a new generation of nanoproduct in biomedical applications. Trends Biotechnol. 2010;28:580–588. doi: 10.1016/j.tibtech.2010.07.006. - DOI - PubMed
    1. Lansdown, A. B. A pharmacological and toxicological profile of silver as an antimicrobial agent in medical devices. Adv Pharmacol2010 (2010). - PMC - PubMed