Toxicity evaluation of magnetic iron oxide nanoparticles reveals neuronal loss in chicken embryo.

Magnetic iron oxide nanoparticles (IONs) display the ability to cross blood - brain barrier and are envisioned as diagnostic and therapeutic applications, but there are few studies on their potential embryonic toxicity in higher vertebrates. This study investigates interaction of IONs with egg albumen and its subsequent toxicity on chicken embryo. Physicochemical interactions of IONs with egg albumen revealed alterations in friccohesity and secondary structural changes due to weak Vander Waals forces. Toxicity assessment of IONs (10, 25, 50, 100, and 200 µg/ml doses) on chicken embryo accounted for 100% mortality at 200 µg/ml dose due to Fe2+ ions overload. However, lower doses (50 and 100 µg/ml) recorded decrement in whole weights and crown-rump lengths of chicken embryo possibly due to ION-albumen interactions. Histology of brain tissue revealed degeneration of neurons (50-60%) at 10-100 µg/ml dose range of IONs. Toxicity studies of IONs with diverse animal models are needed to set a toxicity benchmark for preventing embryonic toxicity prior to its use in biomedical applications. This is the first study on toxicity assessment of IONs in chicken embryo.