Breathe easy capsules

Achim Müller and colleagues at the University of Bielefeld, Germany, have spent many years designing and synthesizing sophisticated inorganic and organometallic supramolecular structures based on molybdenum oxide building blocks. Now, they have produced an artificial capsule with pores that can open and close in a breathing motion. The capsule, reminiscent of a viral shell, could be used to selectively adsorb small molecules that are bigger than the pores at normal size and so trap them within for catalytic, sensor, and separation applications.