A research team led by Dr. Yingying Zhang (Department of Chemistry, Tsinghua University) devised a scheme utilizing silkworms to produce strong, tough silk through feeding them with rare earth ion-modified diets. The rare earth ions can be incorporated into silk fibroin through feeding. And the incorporated ions are capable of forming ion-dipole and cation-π interactions with silk fibroin. These interactions are promising to tune the structures of silk to enhance its mechanical performance.