This short animation for the lab of Charlie Jeynes at University of Exeter introduces ’nanoparticles’ as potential agents for use in the treatment of various diseases, including cancer. Nanoparticles can convert electromagnetic energy into heat, for instance from near-infra-red light, making them attractive candidates for ’thermal’ therapies. The animation shows how this could work and illustrates at some future applications of nanoparticles in medicine.