Large-scale single MoS2 crystals unlocked
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Unusual Li2O sublimation promotes single-crystal growth and sintering
Li2O is rarely used for cathode material synthesis due to its high melting point (1,438 °C). Here we discover that Li2O can sublimate at 800–1,000 °C under ambient pressure, opening new possibilities for cathode synthesis. We propose a mechanism that enables synthesis of single crystals—such as LiNi0.8Mn0.1Co0.1O2 (NMC811) or LiNi0.9Mn0.05Co0.05O2 (NMC90)—without direct contact with Li2O salts. We show that Li2O vapour successfully converts spent polycrystalline NMC811 into segregated single crystals without milling or post-treatment. The Li2O vapour, derived from Li2O solids, diffuses rapidly and reacts with precursors, mimicking a molten-salt environment, which facilitates single-crystal growth. The chemical lithiation process continuously drives Li2O sublimation, sintering the crystals. Single crystals derived from Li2O and fresh precursors or spent polycrystals exhibit outstanding cycling after 1,000 cycles in full cells. The demonstrated Li2O sublimation and its universal role in promoting single-crystal growth provides an effective approach for single-crystal synthesis, scale-up and recycling.
Microscopic crystallographic analysis of dislocations in molecular crystals
Organic molecular crystals encompass a vast range of materials from pharmaceuticals to organic optoelectronics, proteins and waxes in biological and industrial settings. Crystal defects from grain boundaries to dislocations are known to play key roles in mechanisms of growth1,2 and in the functional properties of molecular crystals3,4,5. In contrast to the precise analysis of individual defects in metals, ceramics and inorganic semiconductors enabled by electron microscopy, substantially greater ambiguity remains in the experimental determination of individual dislocation character and slip systems in molecular materials3. In large part, nanoscale dislocation analysis in molecular crystals has been hindered by the low electron doses required to avoid irreversibly degrading these crystals6. Here we present a low-dose, single-exposure approach enabling nanometre-resolved analysis of individual dislocations in molecular crystals. We demonstrate the approach for a range of crystal types to reveal dislocation character and operative slip systems unambiguously.
Crystal structures of monomeric BsmI restriction endonuclease reveal coordinated sequential cleavage of two DNA strands
BsmI, a thermophilic Type IIS restriction endonuclease from Bacillus stearothermophilus, presents a unique structural composition, housing two distinct active sites within a single monomer. Recognition of the non-symmetrical 5’-GAATGC-3’ sequence enables precise cleavage of the top and bottom DNA strands. Synthetic biology interventions have led to the transformation of BsmI into Nb.BsmI, a nicking endonuclease. Here we introduce Nt*.BsmI, tailored for top-strand cleavage, which is inactive on standard double-stranded DNA, but active on bottom-strand nicked DNA, suggesting a sequential cleavage mechanism. Crystallographic structures of pre- and post-reactive complexes with cognate DNA show one major conformational change, a retractable loop possibly governing sequential active site accessibility. The x-ray structures reveal the position of the divalent metal ions in the active sites and the DNA:protein interactions, while the models predicted by Alphafold3 are incorrect. This comprehensive structural and functional study lays a foundation for rational enzyme redesign and potential applications in biotechnology.
Photonic-crystal surface-emitting lasers
High-performance lasers are important to realize a range of applications including smart mobility and smart manufacturing, for example, through their uses in key technologies such as light detection and ranging (LiDAR) and laser processing. However, existing lasers have a number of performance limitations that hinder their practical use. For example, conventional semiconductor lasers are associated with low brightness and low functionality, even though they are compact and highly efficient. Conventional semiconductor lasers therefore require external optics and mechanical elements for reshaping and scanning of emitted beams, resulting in large, complicated systems for various practical uses. Furthermore, even with such external elements, the brightness of these lasers cannot be sufficiently increased for use in laser processing. Similarly, gas and solid-state lasers, while having high-brightness, are also large and complicated. Photonic-crystal surface-emitting lasers (PCSELs) boast both high brightness and high functionality while maintaining the merits of semiconductor lasers, and thus PCSELs are solutions to the issues of existing laser technologies. In this Review, we discuss recent progress of PCSELs towards high-brightness and high-functionality operations. We then elaborate on new trends such as short-pulse and short-wavelength operations as well as the combination with machine learning and quantum technologies. Finally, we outline future research directions of PCSELs with regard to various applications, including not only LiDAR and laser processing, as described above, but also communications, mobile technologies, and even aerospace and laser fusion.
Structural insights into tecovirimat antiviral activity and poxvirus resistance
Mpox is a zoonotic disease endemic to Central and West Africa. Since 2022, two human-adapted monkeypox virus (MPXV) strains have caused large outbreaks outside these regions. Tecovirimat is the most widely used drug to treat mpox. It blocks viral egress by targeting the viral phospholipase F13; however, the structural details are unknown, and mutations in the F13 gene can result in resistance against tecovirimat, raising public health concerns. Here we report the structure of an F13 homodimer using X-ray crystallography, both alone (2.1 Å) and in complex with tecovirimat (2.6 Å). Combined with molecular dynamics simulations and dimerization assays, we show that tecovirimat acts as a molecular glue that promotes dimerization of the phospholipase. Tecovirimat resistance mutations identified in clinical MPXV isolates map to the F13 dimer interface and prevent drug-induced dimerization in solution and in cells. These findings explain how tecovirimat works, allow for better monitoring of resistant MPXV strains and pave the way for developing more potent and resilient therapeutics.
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