A current focus in global health research is to make medical tests that are not just cheap, but virtually free. One such strategy is to start with paper – one of humanity’s oldest technologies – and build a device like a home-based pregnancy test that might work for malaria, diabetes or other diseases. A University of Washington bioengineer recently developed a way to make regular paper stick to medically interesting molecules. The work produced a chemical trick to make paper-based diagnostics using plain paper, the kind found at office supply stores around the world.