Luchini's solution was to build a nanoparticle trap. The concept, like Galileo's telescope, is simple: "It's like a net for catching very small fishes," Luchini says. The spherical nanoparticle, which took two years to perfect, uses hydrogel as its backbone. Inside, a crisscrossing polymer net holds bait, such as acid or dye, which chemically attracts various biomarkers. when lab technicians mix the nanoparticle in with a fresh blood sample, it traps the biomarkers and protects them from enzymes. The sample can then be tested at leisure. So far, Luchini has used nanoparticle traps to produce an early diagnosis of infectious diseases such as Lyme disease and tuberculosis. (The traps can also reveal the presence of human growth hormone in urine, and thus offer a novel way to reveal illegal doping by athletes.) She and her team are also working on nanotraps to find the skin-cancer biomarkers that exist in a person's sweat.