Tallow amphopolycarboxyglycinate-stabilized silver nanoparticles: new frontiers in development of plant protection products with a broad spectrum of action against phytopathogens

Sustainable agriculture calls for minimal use of agrochemicals in order to protect the environment. It has caused an increase in the rate of nanoparticles use, in particular silver nanoparticles (AgNPs) due to their safety for mammals, unique biological activity and a broad spectrum of action against fungal and bacterial pathogens. Until now the use of AgNPs dispersions in the agricultural sector has been essentially limited due to many factors decreased their stability (mixing with other pesticides, presence of electrolytes). We present a versatile synthesis of polyampholyte surfactant (tallow amphopolycarboxyglycinate) stabilized AgNPs. We took a close look at unique aggregation behavior (via dynamic light scattering and UV–vis spectroscopy) and biocidal activity of obtained silver colloids. AgNPs are characterized by exclusively high aggregative stability in the presence of coagulating agents NaNO₃ and NaSO₄ (up to 1 M), during drying/redispergation, and frost/defrost cycles. The dispersion of AgNPs shows high biocidal activity (EC₅₀ is ten times lower than commercial species ones) with respect to Phytophthora infestans and phytopathogenic fungi. This points to the possibility of successful application of silver preparations within agriculture with the goal of partial reduction of the use of toxic and expensive synthetic antibiotics and pesticides. (paper)