Nanoparticles, superstrong and flexible structures such as carbon nanotubes that are measured in billionths of a meter—a diameter thousands of times thinner than a human hair—are used in everything from microchips to sporting goods to pharmaceutical products. But large-scale production of high-quality particles faces challenges ranging from improving the selectivity of the synthesis that creates them and the quality of the synthesized material to the development of economical and reliable synthesis processes.