In this issue, H. Andersson Svahn et al. review the 3D printing of tissue and organ models. How can the spatial and chemical complexity inherent to native tissues and organs be recreated? In a Minireview, J. Janek et al. discuss ambiguities in the nature of discharge products in sodium–oxygen batteries.

In the Communications section, A. Pines et al. present a new device that facilitates the direct dissolution of hyperpolarized ¹²⁹Xe into viscous liquid-crystalline media (see picture). C. Tedesco et al. report on zipping and unzipping within a cyclic peptoid single crystal and Y. Wang et al. describe the design of a bifunctional catalyst for methanol synthesis and carbon–carbon coupling.

• Angewandte Chemie 15/2016: Chemical Complexity,
  Angew. Chem. Int. Ed. 2016, 55 (15).