Nanoscience: Metal-oxide based porous capsules allow supramolecular sphere surface and encapsulation chemistry as well as the study of artificial cell environment interactions, e.g. modeling cation transport through biological membranes. The 20 pores have crown ether function.
Highlighted in: M. Freemantle, 'Artificial Cells Allow Ion Entry: Porous Inorganic Capsules Serve as Models for Biological Ion-Transport Processes', Chemical & Engineering News (News of the Week), Vol. 83, No. 48, November Issue (2005), p. 10. (see also: http://pubs.acs.org/cen/news/83/i48/8348notw6.html and
L. Cronin, Angew. Chem. Int. Ed. 2006, 45, 3576-3578)