When materials and devices are fabricated with tiny dimensions, their properties and applications expand enormously. Small size, which for nanotechnology means less than 100 nm, confers on devices and materials enhanced flexibility and improved performance. We've begun exploiting such properties in a multitude of emerging areas ranging from computing to translational medicine. Yet, just as the promise of nanotechnology becomes more defined, skeptics raise questions about the unforeseen risks this new technology may present for the environment and our health.[1,2]