Evaluation of Green Silver Nanoparticles Fabricated by Spirulina platensis Phycocyanin as Anticancer and Antimicrobial Agents

Abstract

Green nanotechnology has attracted attention worldwide, especially in treating cancer and drug-resistant section 6 microbes. This work aims to investigate the anticancer activity of green silver nanoparticles synthesized by <i>Spirulina platensis</i> phycocyanin (SPAgNPs) on two cancer cell lines: Lung cancer cell line (A-549) and breast cancer cell line (MCF-7), compared to the normal human lung cell line (A138). We also aimed to investigate the bactericidal activity against <i>Staphylococcus aureus</i> ATCC29737, <i>Bacillus cereus</i> ATCC11778, <i>Escherichia coli</i> ATCC8379, and <i>Klebsiella pneumonia</i>, as well as the fungicidal activity against <i>Candida albicans</i> (ATCC6019) and <i>Aspergillus niger</i>. The obtained SPAgNPs were spherical and crystalline with a size of 30 nm and a net charge of -26.32 mV. Furthermore, they were surrounded by active groups responsible for stability. The SPAgNPs scavenged 85% of the DPPH radical with a relative increase of approximately 30% over the extract. The proliferation of cancer cells using the MTT assay clarified that both cancer cells (A-549 and MCF-7) are regularly inhibited as they grow on different concentrations of SPAgNPs. The maximum inhibitory effect of SPAgNPs (50 ppm) reached 90.99 and 89.51% against A-549 and MCF7, respectively. Regarding antimicrobial activity, no inhibition zones occurred in bacterial or fungal strains at low concentrations of SPAgNPs and the aqueous <i>Spirulina platensis</i> extract. However, at high concentrations, inhibition zones, especially SPAgNPs, were more potent for all tested microorganisms than their positive controls, with particular reference to <i>Staphylococcus aureus,</i> since the inhibition zones were 3.2, 3.8, and 4.3 mm, and <i>Bacillus cereus</i> was 2.37 mm when compared to tetracycline (2.33 mm). SPAgNPs have more potent antifungal activity, especially against <i>Aspergillus niger</i>, compared to their positive controls. We concluded that SPAgNPs are powerful agents against oxidative stress and microbial infection.