Effect of mycogenic silver nanoparticles as a biocide on Schistosoma mansoni cercariae and Aedes aegypti larvae and their impact on non-target microcrustaceans

Abstract

Biogenic silver nanoparticles (AgNPs) obtained using extracellular biomolecules from the extremophilic fungus Aspergillus tubingensis (AgNP-AT) present a promising antimicrobial activity. In this study, the effect of AgNP-AT was evaluated against Schistosoma mansoni cercariae, the freshwater snail Biomphalaria glabrata, and larvae of the mosquito Aedes aegypti, and on the non-target aquatic microcrustaceans, Daphnia magna and Cypricercus centrura. AgNP-AT showed high efficacy against cercariae, with a median lethal concentration (LC₅₀) of 0.03 μM after 2 h of exposure. In B. glabrata, blastulae and gastrulae were the most susceptible (LC₅₀ = 1.3 and 1.5 μM, respectively), followed by veliger (LC₅₀ = 2.5 μM) and trochophore (LC₅₀ = 3.8 μM), while adults were less affected (LC₅₀ = 19.0 μM). In A. aegypti larvae, after 48 h of exposure at 10 μM, AgNP-AT induced 95.9% of mortality. Importantly, the non-target microcrustaceans were considerably less sensitive, with LC₅₀ values of 0.68 μM for D. magna and 3.93 μM for C. centrura, both substantially higher than the values observed for cercariae. The selective toxicity of AgNP-AT may be associated with the corona protein on its surface, which modulates a gradual silver ion release allowing specific binding to the target. AgNP-AT showed cercaricidal activity against S. mansoni and was effective in the control of A. aegypti mosquito larvae. These results represent a significant innovation in the field of controlling diseases transmitted by parasites and vectors, with lower toxicity on non-target organisms such as aquatic species.