Green synthesis of silver iodide nanoparticles from Kluyveromyces marxianus M59 beta-glucan: characterization and anticancer activity

Green synthesis of silver iodide nanoparticles (AgI-NPs) using carboxymethyl β-glucan from Kluyveromyces marxianus M59 was conducted to produce environmentally friendly and stable nanomaterials. The AgI-NPs had particle sizes ranging from 29 to 100 nm, exhibited a crystalline structure confirmed by X-ray diffraction, and and showed a characteristic absorption peak at 450 nm. Biological evaluations revealed low antibacterial activity against Listeria monocytogenes (maximum inhibition zone: 1.70 mm at 5 mg/mL), strong antibiofilm activity (66.9% reduction at 5 mg/mL), and significant antioxidant capacity, with the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of 58.9% at 5 mg/mL. Cytotoxicity assays showed selective toxicity toward A549 lung cancer cells (IC50: 23.95 µg/mL at 24 h and 19.13 µg/mL at 48 h) compared to normal L929 fibroblasts (IC50: 130.37 µg/mL at 24 h and 73.69 µg/mL at 48 h). These findings highlight the multifunctional potential of AgI-NPs, emphasizing their antibiofilm, antioxidant, and anticancer activities, and provide a foundation for further investigations into their molecular mechanisms and sustainable applications.