Scaling relationships have been established between certain physical or chemical properties of heterogeneous catalytic reactions. In this Review, these properties, or reactivity descriptors, are described and their ability to predict catalytic performance, and thus enable the rational design of catalysts are outlined. See Zhao et al.

In vivo genome editing requires delivery systems that are efficient, safe and tissue specific. This Review outlines the materials and delivery strategies currently used, and the challenges and potential solutions in in vivo genome editing, aiming to stimulate further development of engineered materials for in vivo delivery of genome-editing machinery. See Tong et al.

2D materials exhibit diverse properties and can be integrated in heterostructures: this makes them ideal platforms for quantum information science. This Review surveys recent progress and identifies future opportunities for 2D materials as quantum-dot qubits, single-photon emitters, superconducting qubits and topological quantum computing elements. See Liu & Hersam.

Despite their excellent macroscopic operational parameters, halide perovskites exhibit heterogeneity in materials properties at all lateral and vertical length scales. This Review discusses heterogeneity in halide perovskites and assesses the impact of these non-uniformities on their optoelectronic properties and how heterogeneity may be beneficial for device properties.

Hexagonal boron nitride (hBN) is highly sought after for mid-IR nanophotonics, nonlinear and quantum optics, and as an efficient UV emitter. This Review surveys the synthesis, physical properties and applications of hBN.

Electron beams in a transmission electron microscope can be used to manipulate matter atom-by-atom. This Review surveys recent advances and discusses how the development and integration of machine learning, theory, feedback and instrumentation will push the field forward. See Dyck et al.

The field of immunoengineering is progressing at high speed, and materials science greatly contributes to this progress by providing smart and controllable tools for immunotherapy with the aim to improve clinical outcomes. In this focus issue, we explore materials science strategies and opportunities for cancer immunotherapy and for modulating the immune system in autoimmune diseases and tissue regeneration.

Breakthroughs in crystal structure prediction have enabled the discovery of materials and of physical and chemical phenomena. This Review surveys structure prediction methods and presents examples of results for different classes of materials. See Oganov et al.

Oxide superlattices reveal emergent phenomena if the balance between competing degrees of freedom is altered. In this Review, synthetic approaches to tap the properties of competing ground states are described, focusing on an example yielding a room-temperature multiferroic and another example producing polarization skyrmions. See Ramesh & Schlom

Chalcogenide phase-change materials (PCMs) are leading candidates for non-volatile memory and neuro-inspired computing devices. This Review focuses on the crystallization mechanisms of PCMs as well as the design principles to achieve PCMs with high switching speeds and good data retention. See Zhang et al.

Ingestible electronics can be used as clinical tools for diagnosis and therapy. In this Review, drug delivery applications and sensor technologies are discussed alongside the challenges and opportunities for clinical translation, such as safety, powering and communication. See Steiger et al.

The dynamics of epithelial tissues play a key role in tissue organization, both in health and disease. In this Review, the materials and techniques for the study of epithelial movement and mechanics are discussed and epithelia as active matter are investigated from theoretical and experimental perspectives. See Xi et al.