Inspired by Boolean binary algebra, an approach to design electromagnetic metamaterials with desired permittivity by using just two elemental building blocks is demonstrated analytically and numerically.

Article p1115; News & Views p1080

IMAGE: ELLA MARUSHCHENKO AND ALEX TOKAREV

COVER DESIGN: DAVID SHAND

Crystalline silver nanoparticles can be deformed at room temperature and without generating dislocations through the diffusion of surface atoms, as high-resolution transmission electron microscopy and atomistic simulations show.

Letter p1007; News & Views p999

IMAGE: YAN LIANG

COVER DESIGN: DAVID SHAND

The selective separation of molecules with similar size and shape at low concentration in air is an important technological challenge. A porous organic-cage molecule is now shown to exhibit unprecedented performance for the separation of rare gases, with selectivity arising from a precise size match between the rare gas and the organic-cage cavity.

Article p954

IMAGE: ADAM KEWLEY

COVER DESIGN: DAVID SHAND

The performance of solar cells based on organic–inorganic perovskites strongly depends on the device architecture and processing conditions. It is now shown that solvent engineering enables the deposition of very dense perovskite layers on mesoporous titania, leading to photovoltaic devices with a high light-conversion efficiency and no hysteresis.

Article p897; News & Views p845

IMAGE: JUN HONG NOH AND SANG IL SEOK

COVER DESIGN: DAVID SHAND

The excitations that determine the low-temperature properties of ferromagnetic materials are called spin waves. Using a combination of inelastic electron tunnelling spectroscopy and numerical simulations, the spin waves occurring in a one-dimensional chain of iron atoms deposited on Cu2N are now imaged, and their dynamics examined.

Letter p782; News & Views p770

IMAGE: SANDER OTTE

COVER DESIGN: DAVID SHAND

Block copolymers can self-assemble into nanostructures that simultaneously facilitate ion transport and provide mechanical stability. Highly asymmetric charge cohesion effects are now shown to induce the formation of nanostructures with percolated phases desired for ion transport. This strategy could lead to the design of enhanced battery electrolyte materials.

Letter p694

IMAGE: MARK SENIW

COVER DESIGN: DAVID SHAND

Cell behaviour is in part regulated by the rigidity of their environment, yet the underlying mechanisms have remained unclear. It is now shown for breast myoepithelial cells expressing two types of integrin that rigidity sensing and adaptation can be explained by a clutch-bond model that considers the different rates of binding and unbinding between the integrins and the extracellular matrix.

Article p631; News & Views p539

IMAGE: ALBERTO ELOSEGUI, XAVIER SERRA-PICAMAL AND RAIMON SUNYER

COVER DESIGN: DAVID SHAND

The electronic properties of bismuth under an applied magnetic field have latterly become a topic of interest. An angle-resolved magnetostriction approach is now used to provide thermodynamic evidence for unusual symmetry-breaking effects.

Letter p461

IMAGE: UTA PRAUTZSCH AND ROBERT KüCHLER

COVER DESIGN: DAVID SHAND

Cuprate superconductors have found limited application for high-field magnets because of difficulties related to grain boundaries. Now, this issue is partially overcome and round wires suitable for magnetic coils are fabricated from Bi2Sr2CaCu2O8–x.

Article p375; News & Views p326

IMAGE: PETER LEE AND MAXIME MATRAS

COVER DESIGN: DAVID SHAND

Colloidal particles dispersed in liquid crystals induce nematic fields and topological defects that are dictated by the topology of the colloidal particles. However, little is known about such interplay of topologies. It is now shown that knot-shaped microparticles in liquid crystals induce defect lines that get entangled with the colloidal knots, and that such mutually tangled configurations satisfy topological constraints and follow predictions from knot theory.

Letter p258; News & Views p229

IMAGE: ANGEL MARTINEZ AND IVAN I. SMALYUKH

COVER DESIGN: DAVID SHAND

Imaging intracellular compartments, cells and tissues enables more accurate diagnosis and treatment of disease. In this focus issue we highlight the latest developments and clinical translation of materials-based technologies for imaging cells or the disease microenvironment with the promise of improved therapeutic outcomes.

Editorial p99; Commentary p106; Commentary p110; News & Views p122; Review Article p125; Article p204

IMAGE: RAINER KOHLER, MIKAEL PITTET AND RALPH WEISSLEDER

COVER DESIGN: DAVID SHAND

Size effects and geometry can significantly modify the properties of nanoparticles with direct impact on their biocompatibility and chemical reactivity. Using high-resolution electron microscopy it is now shown that strain gradients induced in the oxide shell of cuboid Fe nanoparticles can lead to oxide domain formation and shape evolution of the particles.

Letter p26

IMAGE: ROLAND KRöGER AND AMISH SHAH

COVER DESIGN: DAVID SHAND