European researchers are working to develop nano-scale chemical sensors, in the hopes of devise a device that could test male urine for the presence of prostate cancer cells. The technology, like other nano-based detection devices, exploits the fact that researchers can attach many different types of molecules to carbon nanotubes. These molecules will interact with cancer cells present in the urine, producing a measurable change in theconductivity of the nanotubes. The result? Devices that smell cancer in urine. The video also describes attaching gold nanoparticle "markers" to make cancer cells more visible.