Reviews & Analysis

This Review outlines the ability of DNA to direct the organization of particle-based building blocks into crystalline architectures. These advancements permit programmable control of each structural element of colloidal crystalline materials and enable the design of functional and responsive behaviours.

Metal halide perovskite nanostructures are promising materials for optoelectronic applications. In this Review, we discuss the synthesis and properties of 1D and 2D single-crystal perovskite nanostructures, examine potential optoelectronic applications and highlight recent studies in which these nanostructures have been used to study the fundamental properties of perovskites.

Laser pulses can trigger fast changes in magnetic state, facilitating new magnetic data storage and memory devices. This Review outlines the mechanisms of all-optical switching and the materials suitable for the optical control of magnetism and tests these mechanisms and materials in terms of speed, accompanying dissipations and scalability. Finally, the large-scale integration of devices in memory applications with low-energy dissipations is discussed.

Mucus is a 3D hydrogel composed of mucins that houses the human microbiome. Mucus guides microbial cell fate and is involved in the suppression of pathogenic bacteria. In this Review, the authors discuss the design of synthetic mucins for the investigation of mucus–microbiome interactions and for applications in 3D in vitro cell culture.

Shape-memory materials can generate programmable movements triggered by an external stimulus, such as an environmental change. In this Review, the authors discuss mechanisms, fabrication schemes, characterization methods and applications of the one-way shape-memory effect enabling shape recovery and of reversible shape-memory effects exhibiting actuation behaviour.

Man-made fibrillar hydrogels mimic the structure of filamentous extracellular matrices and can be used as biomaterials for 3D cell culture and tissue engineering. In this Review, the authors discuss the design and properties of fibrillar hydrogels and explore different building blocks, assembly mechanisms, properties and applications.

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, which will aid the development of PCM-based universal memory and neuro-inspired devices.

Liquid cell electron microscopy provides a unique combination of spatial and temporal resolution, which is useful for imaging static and dynamic processes in liquids. In this Review, we discuss the resolution expected when imaging liquid specimens in transmission electron microscopy and scanning transmission electron microscopy and consider the benefits of spherical and chromatic aberration for resolution, image interpretability and dose efficiency.

3D electrodes with interconnected and interpenetrating pathways enable efficient electron and ion transport. In this Review, the design and synthesis of such 3D electrodes are discussed, along with their ability to address charge transport limitations at high areal mass loading and to enable composite electrodes with an unprecedented combination of energy and power densities in electrochemical energy storage devices.

Ingestible electronics can be used as clinical tools for diagnosis and therapy. In this Review, the authors discuss clinical applications of ingestible electronic devices and highlight materials and sensor technologies, drug delivery applications and major challenges and opportunities for clinical translation, such as safety, powering and communication.

The dynamics of epithelial tissues play a key role in tissue organization, both in health and disease. In this Review, the authors discuss materials and techniques for the study of epithelial movement and mechanics and investigate epithelia as active matter from a theoretical and experimental perspective.

Holographic duality establishes a connection between quantum gravity and strongly correlated many-body systems, providing a unique opportunity to study quantum black holes in the laboratory. In this Review, Sachdev–Ye–Kitaev models, which illustrate this duality, are discussed, along with their potential realization in ultracold gases, graphene, semiconducting nanowires and 3D topological insulators.

Combining low-dimensional and 3D perovskites is a promising approach to achieve stable and efficient solar cells. In this Review, we discuss the structural, optical and photophysical properties of low-dimensional perovskites, compare the stability and efficiency of 2D and 3D perovskite devices, and consider 2D/3D composites as a strategy to increase the stability of perovskite solar cells.

Inorganic semiconductor devices enable the formation of functional interfaces with cells and tissues to detect or provide physical stimuli. In this Review, inorganic semiconductor materials are discussed for electronic and optoelectronic sensing, optoelectronic and photothermal stimulation and photoluminescent in vivo imaging.

Sound waves can be manipulated using structurally designed 2D materials of subwavelength thickness. This emerging field, namely, acoustic metasurfaces, is driven by the desire to control acoustic wave propagation using compact devices.

Cells can be transplanted into the body to both repair injured or diseased tissue and restore tissue function. This Review discusses how biomaterial design strategies can be used to improve cell survival, influence the fate of transplanted cells, and favourably manipulate the host microenvironment and the immune system.

Graphene-integrated photonics is a platform for wafer-scale manufacturing of modulators, detectors and switches for next-generation datacom and telecom systems. This Review describes how these functions can be achieved with graphene layers placed on top of optical waveguides, acting as passive light guides, thus simplifying the current technology. In addition, a roadmap of the technological requirements for the datacom and telecom markets is presented.

A responsive material in the form of a polymer or hydrogel can be combined with a signal transduction element in the form of plasmonic particles, resulting in hybrid plasmonic polymer nanocomposites. In this Review, the fabrication and applications of such nanocomposites are discussed. The applications described focus on optical data storage, sensing and imaging and the use of photothermal gels for in vivo therapy.

There is increasing interest in the liquid, glass and amorphous solid states of coordination polymers and metal–organic frameworks. In this Review, we discuss the background and terminology of this emerging field, categorize example structures and provide an outlook for the future direction of the field.

This Review discusses how biomaterials can be used to recreate and understand the influence of specific tumour microenvironment properties on cancer progression and highlights materials-based strategies to capture, detect and assess metastatic cancer cells in vitro and in vivo.