In this issue, S. Q. Yao et al. review the design of nanomaterials for mitochondria-targeted nanotherapeutics, and O. Zelder et al. summarize research on metabolic engineering for the fermentative production of chemicals. The Minireviews deal with reaction mechanisms of layered lithium-rich cathode materials (G. Wang et al.) and nucleic acid aptamers for molecular diagnostics and therapeutics (W. Tan et al.). M. H. Stenzel shares a Viewpoint on drug loading of nanoparticles, and W. A. Nugent and T. V. RajanBabu discuss titanium(III) chemistry in an Essay.

In the original research section, W. Richtering et al. describe stiffness tomography of ultrasoft nanogels by atomic force microscopy (see picture). G. Guichard et al. found the structural basis for α-helix mimicry and inhibition of protein–protein interactions with oligourea foldamers. B. Peng et al. succeeded in the Z-selective α-arylation of α,β-unsaturated nitriles via a [3,3]-sigmatropic rearrangement. D. Stalke et al. provide insight into the topology and the formation of a genuine ppσ bond in trichloride monoanions.

• Angewandte Chemie 5/2021: Mechanistic Mysteries,
  Angew. Chem. Int. Ed. 2020, 60 (5).