Nanotheranostics — nanoparticle-based systems combining diagnostic and therapeutic functions — hold great promise, but their implementation in the clinic requires overcoming technical, manufacturing, regulatory and economical challenges for their safe and effective clinical translation. The cover image shows an artist’s impression of the Valley of Death that needs to be crossed to reach real-life therapies: the snake made out of different nanomedicines wraps around the rod of Asclepius, symbolizing healing, medicine and pharmacy to help scientists, doctors and patients to climb up the slope. See Peter J. Gawne et al.

In situ self-assembly is advantageous for cancer therapy and imaging because of the efficient deep-tumour targeting, enhanced blood circulation and negligible drug resistance of the resulting nanomedicines, and can be activated by various endogenous and exogenous stimuli in both the extracellular and the intracellular milieu. The cover image illustrates dynamic in situ self-assembly within a cancer cell. See Jaewon Kim et al..

For deaf scientists who use American Sign Language (ASL), communicating about science can be a challenge when the language does not yet have the necessary tools for it. Many of these researchers are now expanding ASL for scientific contexts. The cover illustrates a new sign for 'crystal' recently developed by deaf scientists for possible use by the American Sign Language community. An example video is available at Quantum ASL. See our Viewpoint and Editorial

Sodium-ion batteries (SIBs) are an emerging type of sustainable battery, but for them to be environmentally viable they need to be recycled. Strategies to recycle spent SIBs should be taken into account already during the initial stages of commercialization to ensure that SIBs are designed for ease of recycling, efficiency and low operation costs. The cover image shows schematic illustrations of a qualified and a spent SIB. See Yun Zhao et al.

Integrating various 2D materials and 3D nanomembranes via van der Waals interactions enables novel hetero-integrated photonic layouts and ways to explore exotic nanophotonic phenomena. The cover image illustrates a van der Waals heterostructures comprising a variety of functional layers. See Yuan Meng et al.

Understanding the protein corona can advance nanomedicinal developments and elucidate how nanomaterials impact the environment. The cover image shows biomolecular coronas on the surface of nanoparticles. See Morteza Mahmoudi et al.

Monolayer-protected metal clusters are versatile nanomaterials that can be engineered, in principle, with atomic precision. The cover illustrates how these materials can be iteratively designed and understood through a tight interplay between in silico and experimental approaches. See María Francisca Matus & Hannu Häkkinen

One of the most advanced and challenging topics in modern reticular chemistry is structure multivariation. The image shows building blocks assembling in an ordered material with aperiodic composition, forming countless local sequences. Restricting the variety of sequences by precise synthetic control affords crystals with distinct local structures and highly specific emergent properties. See Stefano Canossa et al.

Ultrafast spectroscopies, and in particular three emerging techniques – attosecond transient absorption spectroscopy, solid-state high-harmonic generation spectroscopy and extreme ultraviolet-second harmonic generation spectroscopy – enable the characterization of quantum materials and of their functional properties. The cover shows an artistic rendering illustrating coupled degrees of freedom in a quantum material probed by ultrafast light. See Alfred Zong et al. [Note: the cover line has been updated to read "attosecond transient absorption spectroscopy."]

The rapidly growing complexity of 3D in vitro models calls for new and more versatile chip designs to overcome limitations of permanently sealed microfluidic cell culture devices. The cover shows an artistic rendering illustrating the concept of reversible clamping strategies, such as in Lock-and-Play devices, which will play a key role in developing next-generation microphysiological systems. See Daniel J. Teixeira Carvalho, Lorenzo Moroni & Stefan Giselbrecht

Aqueous batteries are old technologies, but as their performance characteristics have developed thanks to the introduction of new materials and cell designs, they are emerging as a contender for energy-storage solutions for the needs of modern society. The cover shows an artistic image of the evolution of an aqueous battery into a modern technology. See Yanliang Liang & Yan Yao

Physiological mechanosensory proteins need to constantly – and reversibly – unfold and refold under mechanical forces. Consequently, the elasticity of individual proteins underpins diverse macroscopic phenomena in biology. The cover shows the complex energy landscape that defines the conformational dynamics of a single protein when exposed to mechanical load. See Amy E. M. Beedle and Sergi Garcia-Manyes