Plant-derived chitosan nanoparticles: antibacterial and improved crop performance under drought stress

This study presents plant-assisted synthesis of chitosan nanoparticles (CNPs) using Adansonia digitata extract via ionic gelation, demonstrating their dual role as antimicrobial agents and enhancers of seed germination under polyethylene glycol (PEG)-induced osmotic stress, a model for drought conditions. The CNPs were characterized by ultraviolet-visible spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and evaluated against Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). Seed germination assays involved soaking seeds in a one mg/mL CNP solution for 12 hours. Results revealed that CNPs were efficiently produced via ionic gelation of chitosan with TPP in the presence of A. digitata extract, resulting in spherical particles with a peak absorption at 339 nm and an average size of 13.06 ± 0.05 nm. The nanoparticles exhibited strong antibacterial activity, particularly against E. coli, and significantly enhanced seed germination and growth under both normal and water-limited conditions. These findings highlight that integrating plant-derived bioactive compounds into chitosan nanoparticles not only boosts antimicrobial properties but also improves plant resilience to osmotic stress. This dual functionality positions plant-based CNPs as a sustainable strategy to address drought and pathogen-related challenges in agriculture.