Silver nanoparticles fabricated using phycocyanin from Arthrospira platensis: green synthesis, physicochemical characterization, and biological activities.

BACKGROUND: Cyanobacteria and their bioactive components represent a promising potential for the green synthesis of nanoparticles. This work investigates the physicochemical characteristics and biological activities of silver nanoparticles (PC-AgNPs) synthesized using phycocyanin, a photosynthetic pigment extracted from the cyanobacterium Arthrospira platensis Pc-005. RESULTS: The phycocyanin-derived AgNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy Dispersive X-Ray Spectroscopy (EDX), and Dynamic light scattering (DLS). Physicochemical analysis confirmed the formation of PC-AgNPs, and revealed their nanoscale size, crystalline nature and purity. PC-AgNPs demonstrated a UV-Vis absorption peak at 410 nm. TEM analysis revealed that phycocyanin-derived AgNPs were spherical in shape with an average diameter of 20.0 ± 4.2 nm. XRD and EDX analyses confirmed the crystallinity and purity of PC-AgNPs. FTIR analysis revealed the involvement of phycocyanin functional groups in AgNPs formation. The results demonstrated that PC-AgNPs exhibited strong antimicrobial activity against opportunistic pathogenic bacteria Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, as well as fungi Aspergillus flavus, Penicillium aurantioviolaceum, and Trichoderma viride. The findings indicated that significantly higher concentration of PC-AgNPs was needed to achieve antifungal activity compared to antibacterial activity. The PC-AgNPs also affected the activity of crucial antioxidant enzymes, such as superoxide dismutase and catalase, which play key role in the bacterial defense against oxidative stress induced by AgNPs. Moreover, PC-AgNPs demonstrated significant concentration-dependent anticancer activity against A549 adenocarcinoma cells. They also inhibited key angiogenic factors, including VEGF-A and MMP-2, as well as inflammation-related markers such as TNF-α and COX-2. CONCLUSION: Thus, this study provides a comprehensive physicochemical and biological characterization of silver nanoparticles derived from the phycocyanin of A. platensis. The PC-AgNPs exhibit a broad spectrum of biological activities, underscoring their promising potential for innovative applications in biomedical and biotechnological fields.