Regulating growth cone motility and axon growth by manipulating targeted superparamagnetic nanoparticles

Abstract

Central nervous system (CNS) neurons fail to regenerate after injury or disease due, in part, to a reduced intrinsic axon growth ability, which is regulated at the growth cone. Recently, we showed that growth cone motility can be regulated by applying a magnetic field to superparamagnetic iron oxide nanoparticles (SPIONs) targeted either intracellularly to signaling endosomes or extracellularly to cell surface receptors. By applying mechanical forces to extracellular SPIONs, filopodia can be elongated and the rate and the direction controlled. Here, we describe the methods for each of these approaches with additional notes on important caveats and experimental design considerations. These methods offer new approaches to studying growth cone motility and axon growth biology, expanding our knowledge and thus our ability to develop new therapies to promote axon regeneration after nervous system trauma or disease.