In vitro toxicity and uptake of magnetic nanorods

In this paper we investigate the internalization and cytotoxicity of nanostructured materials having the form of elongated rods, with diameter of 200 nm and lengths 1 - 10 urn. The rods were made from the controlled aggregation of sub-10 nm iron oxide nanoparticles. Recently, we have shown that the nanorods inherited the superparamagnetic property of the particles. These rods can actually be moved by the application of an external magnetic field. Here we evaluate the in vitro toxicity of the magnetic nanorods by using MTT assays on NIH/3T3 mouse fibroblasts. The toxicity assays revealed that the nanorods are biocompatible, as exposed cells remained 100% viable relative to controls over a period of a few days. Optical microscopy allows to visualize the rods inside the cells and to determine their number per cell. Roughly 1/3 of the total incubated rods were uptaken by the fibroblasts.