Personal electronic devices are a growing source of the world’s electronic waste. Many of these products use nanomaterials, but little is known about how nanoparticles interact with the environment. Now chemists have discovered that when certain coated nanoparticles interact with living organisms it results in new properties that cause the nanoparticles to become sticky. Nanoparticles with 5-nanometer diameters form long kelp-like structures that are microns in size. The impact on cells is not known.