Chitosan coating does not prevent the effect of the transfer of green silver nanoparticles biosynthesized by Streptomyces malachitus into fetuses via the placenta

Green synthesized nanoparticles are more advantageous over conventionally prepared ones due to less toxicity, production cost, and environmental hazards. With the widespread of the utilization of nanoparticles, little is known about the maternal-fetal transplacental transfer of green nanoparticles. We have biosynthesized silver nanoparticles using metabolites of Streptomyces malachitus and sunlight then coated them with chitosan. These nanoparticles have been characterized and intraperitoneally administered at doses of 100 mg/kg on the 6^th, 8^th, and 10^th gestational days. On the 18^th day of pregnancy, both coated and non-coted NPs were detected in different maternal tissues, placenta, and in fetuses, as determined by estimation of silver content and observation by electron microscopy. Chitosan coating decreased the silver content in different tissues, maybe due to the larger size of coated nanoparticles that retards the transfer. The toxic effects on maternal and fetal tissues were proportional to their silver content, as determined by the liver and kidney functional analysis of pregnant rats and the ultrastructural and histopathological examination of the maternal liver, placenta and fetal liver. The present data suggest that green silver nanoparticles biosynthesized by Streptomyces malachitus cross the placenta and have toxic effects on maternal tissues, placenta, and fetus. Chitosan coating of these nanoparticles decreases the transfer, and consequently, the toxicity. However, it does not prevent this toxicity.