Ma, K. et al. Nature 558, 577–580 (2018).
Self-assembled nanostructures with highly symmetrical, cage-like polyhedral shapes are usually made of programmable organic biomaterials such as DNA. Wiesner and colleagues have now developed a system for the self-assembly of inorganic silica nanostructures that are directed by surfactant micelles. The researchers took advantage of cryo-EM and single-particle 3D reconstruction to accurately identify <10-nm individual silica nanoparticles with dodecahedral cage-like features, called ‘silicages’. It is likely that these nano-sized silicages are formed via Coulomb interaction between positively charged surfactant micelles and negatively charged silica clusters in aqueous solutions. This micelle-directed assembly method enables researchers to distinguish the inside and outside of the cage, which holds great potential for applications ranging from catalysis to drug delivery. Additionally, these self-assembled nanoscale inorganic cages are not limited to silica materials, but also can be produced from gold, silver, and vanadium oxide.