Harnessing Tolypothrix sp. A-8 for biogenic synthesis of silver oxide nanoparticles (AgONPs) for multifunctional biomedical applications

Green nanotechnology leverages biological systems for the sustainable synthesis of nanomaterials, offering an eco-friendly alternative to conventional methods. In this study, we report the phyco-synthesis of silver oxide nanoparticles (AgONPs) using an aqueous extract of Tolypothrix sp. A-8, a cyanobacterium rich in bioactive metabolites that serve as both reducing and capping agents. Synthesis was optimized by controlling key physicochemical parameters (reaction time, precursor concentration, temperature, and pH) to maximize yield. The resulting nanoparticles were comprehensively characterized using X-Ray Diffraction, Ultraviolet Visible Spectroscopy (UV), Fourier Transform Infrared Spectroscopy, Dynamic Light Scattering, Scanning Electron Microscopy, and Energy-Dispersive X-ray Spectroscopy. The AgONPs demonstrated significant anti-leishmanial activity, with IC 50 values of 10.43 µg/mL against promastigotes and 32.43 µg/mL against amastigotes of Leishmania tropica , and an LD 50 of 45 µg/mL against Artemia salina . In anticancer assays against HCT-116 colorectal carcinoma cells, the nanoparticles induced cytotoxicity, with an IC 50 of approximately 8512 µg/mL. They also exhibited notable antioxidant potential, with total antioxidant capacity and total reducing power reaching 58.4% and 51.4%, respectively, at 300 µg/mL. The AgONPs were highly biocompatible, showing non-hemolytic effects at concentrations up to 200 µg/mL (3.2% hemolysis) and an IC 50 of 918.2 µg/mL against human macrophages, confirming their non-toxic nature. Anti-inflammatory activity was confirmed via human red blood cell membrane stabilization, with a 62.8% reduction in hemolysis. Furthermore, the nanoparticles demonstrated dose-dependent anti-diabetic potential, achieving 23.3% glucose scavenging at 900 µg/mL. Antimicrobial assays revealed potent activity, with minimum inhibitory concentrations of 50 µg/mL against Botrytis cinerea , Staphylococcus aureus , and coagulase-negative Staphylococcus , while Bacillus subtilis was the least susceptible bacterial strain (MIC: 150 µg/mL). This study pioneers Tolypothrix sp. A-8 as a scalable biofactory for the sustainable production of multifunctional AgONPs. With their potent, quantitative bioactivities and excellent biocompatibility, these nanomaterials hold significant promise for next-generation nanotherapeutics, including applications in wound healing, targeted drug delivery, and the management of leishmaniasis, cancer, inflammation, and diabetes.