Steerable Nanobots for Diagnosis and Therapy

This paper reviews the synthesis of magnetic multilayerd nanowires that have a wide range of applications. Specifically of interest in this review are the applications of magnetic manipulation and separation of cells, which are important for potential cancer therapies. Compared to other magnetic nanoparticles in use today, the nanowires have the advantage of being ferromagnetic and also having high aspect ratios that enable barcoding. These nanobots are synthesized inside nanoporous oxide templates in large batches (1012 per square inch), and they can be composed of any magnetic metal, alloy, or multilayer that can be electroplated. Specific details for the electrochemistry of Galfenol deposition are given. Galfenol is an exciting new magnetostrictive material with durable mechanical properties. Next, a protocol is described for full removal of the growth contact prior to release of the nanobots from their oxide template. This mitigates aggregation which inhibits cellular uptake. Feasibility of manipulation and separation was shown using canine bone cancer (osteosarcoma) cells which internalized the nanobots, enabling magnetic cellular control. In addition, initial toxicity studies indicate that the nanobots are not cytotoxic. These studies merely scratch the surface of the potential use of nanobots for diagnosis and therapy in the near future.