(421ah) Development of New Generations of Environmentally Benign Antimicrobial Nanoparticles from Ag+ Functionalized Lignin

One of the most widely used classes of nanomaterials to date is the silver nanoparticles (AgNPs), which possess antimicrobial, antisporal and antifungal action. The application of AgNPs, however, has been problematic due to their relatively high price and concerns about the environmental impact of the persistent nanoparticles. We will report the results of the development and testing of a novel class of functionalized, environmentally-benign nanoparticles (EbNPs) that serve as highly efficient microbicidal substitutes of the AgNPs. The EbNPs have a lignin core infused with optimal amount of Ag⁺ ions to achieve antimicrobial activity. They are coated with polyelectrolyte to increase particle adherence to microbes. The active Ag⁺ ions are released during the targeted adsorption of the surface-modified particles onto bacterial membranes. The resulting engineered nanoparticles exhibited higher antimicrobial activity than common AgNPs and silver nitrate towards a number of microbes and human pathogens, including E. coli, Pseudomonas aeruginosa and Ralstonia sp. High-throughput screening showed that the silver-infused EbNPs appear less toxic to mammalian cells in comparison than AgNPs or silver nitrate. Other types of engineered biodegradable nanoparticles loaded with active ingredients and having functionalized surfaces could find applications in many industries, while reducing potential human health and environmental impact.