Abstract
Nanotechnology opens new applications in many fields including medicine. Among all metallic nanoparticles, silver nanoparticles (silver NPS) have proved to be the most effective against a large variety of organisms including toxic cyanobacteria. Silver NPs were biosynthesized in vivo with different alga species namely, Spirulina platensis, Chlorella vulgaris and Scenedesmus obliquus following two scenarios. First: by suspending a thoroughly washed algae biomass in 1 mM aqueous AgNO3 solution. Second: by culturing them individually in culture media containing the same concentration of AgNO3. Silver NPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FTIR) spectroscopy. The biosynthesized silver NPs were tested for cytotoxic activity against a cancer promoter cyanobacteruim Microcystis aeruginosa, considering effects on cell viability and chlorophyll content. The surface plasmon band indicated the biosynthesis of silver NPs at ~400 nm. Transmission electron microscopy (TEM) revealed that the silver NPs had a mean average size below 100 nm. Energy-dispersive analysis X-ray (EDX) spectra confirmed the presence of silver element. FTIR spectral analyses suggested that proteins and or polysaccharides may be responsible for the biosynthesis of silver NPs and (-COO-) of carboxylate ions is responsible for stabilizing them. The toxic potentialities of the biosynthesized silver NPs against the cancer promoter cyanobacterium, Microcystis aeruginosa showed high reduction in viable cells count and the total chlorophyll content. The potential activity of the biosynthesized silver NPs from the studied algae species against Microcystis aeruginosa cells is expected to be mainly mediated by the release of silver ions (Ag+) from the particle surface and bioactive compounds as indicated by FTIR analysis.
Highlights
Cancer is already a major health problem
Fourier Transform Infra-red (FTIR) analysis )7,5 analyses were carried out to identify the possible biomolecules responsible for the reduction of silver ions and the capping of the bioreduced silver NPs synthesized by different micro algal species
The results show that using silver NPs produced by S. platensis, C. vulgaris and Sc. obliquus, have reduced the chlorophyll content of cyanobacterium by % 20.3±0.4, % 34.7±0.3, and % 41.1±0.5 respectively
Summary
Cancer is already a major health problem. It is the second main cause of mortalities in the modern world after heart diseases, with more than 10 million new cases every year. This outline is expected to rise in the few decades. Around one in three people will be diagnosed with cancer throughout their lifetime (Siegel et al, 2012). The lifestyle changes suggest that the burden of neoplasia will become heavier over time, especially with increasing obesity and aging of what are still youthful populations (Salim et al, 2009). The importance of environmental exposure to contaminants has been KLJKOLJKWHG 6DÀ
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