Cancer being cured, humans living to be 150 years old, therapies tailored to the individual patient – science fact or science fiction? Nanotechnologists are discovering and developing new ways of diagnosing, treating, and monitoring diseases, which may make these concepts that seem like science fiction now, reality in the very near future. Indeed, some of the biggest breakthroughs being made in nanotechnology today apply to the medical field and include the development of highly sensitive and selective, point-of-care medical diagnostic tools, the first ways of detecting and genetically identifying circulating tumour cells, and powerful new methods for effecting gene regulation using novel nanostructures called spherical nucleic acids. These methods have the potential to change the way we study and treat some of the world's most debilitating diseases, including cancer, cardiovascular disease, and Alzheimer's disease. Come and hear about these small structures and how they are making a big impact on biology and medicine.