Stable and Highly Steerable Magnetic Nanorobots Demonstrate Therapeutical Functionality in Crowded Biological Media.

Magnetic nanorobots primarily composed of ferromagnetic materials have been extensively investigated for their potential medical applications. Here, we have designed and developed superparamagnetic iron oxide nanoparticles (SPIONs)-functionalized nanorobots (SPIONs-NR), a system that is significantly smaller in size and has larger magnetic anisotropy and steerability than most previously reported superparamagnetic microrobots. We demonstrate that the nanorobots are highly stable against magnetic agglomeration, even at high densities. Due to their smaller size, they can be controllably steered through crowded biological media, which was not possible before. We have maneuvered the robots through the extracellular matrix to target and annihilate malignant cells via magnetic hyperthermia-induced localized heating. Collectively, these properties make SPIONs-NR promising candidates for nanomedicine applications.