The invention provides nanoparticles, methods for making nanoparticles, and methods for using nanoparticles. An important attribute of a drug delivery system is its ability to allow for spatial and temporal regulated drug release, thereby minimizing side effects and improving therapeutic efficacy of conventional pharmaceuticals. Iron oxide nanoparticles (NPs), specifically Fe304 nanoparticles, possess many appropriate qualities that make them a viable choice for drug delivery.