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Abstract Engineered living materials (ELMs) are an emerging class of biohybrid materials with genetically programmable functionalities. Integrating ELMs with 3D bioprinting synergizes their biological programmability with the geometry‐driven functionality of 3D‐printed constructs, transforming these materials into practical products and engineering solutions. This integration also introduces a new paradigm in additive manufacturing that harnesses the “livingness” of encapsulated microorganisms as an active element in the fabrication process to create adaptive and evolving 3D constructs. This Perspective presents recent advances in 3D bioprinting and discusses current developments at the intersection of 3D bioprinting and ELMs. It highlights opportunities at the interface of these two emerging fields, including understanding the interactions between living and nonliving components of ELMs for bioink design, incorporating synthetic biology into bioprinting workflows, utilizing microbial growth as a postprinting fabrication process, and integrating shape‐morphing materials to enable the 4D printing of ELMs. 

Abstract Stimuli‐responsive peptides, particularly pH‐responsive variants, hold significant promise in biomedical and technological applications by leveraging the broad pH spectrum inherent to biological environments. However, the limited number of natural pH‐responsive amino acids within biologically relevant pH ranges presents challenges for designing rational pH‐responsive peptide assemblies. In our study, we introduce a novel approach by incorporating a library of non‐natural amino acids featuring chemically diverse tertiary amine side chains. Hydrophobic and ionic properties of these non‐natural amino acids facilitate their incorporation into the assembly domain when uncharged, and electrostatic repulsion promotes disassembly under lower pH conditions. Furthermore, we observed a direct relationship between the number of substitutions and the hydrophobicity of these amino acids, influencing their pH‐responsive properties and enabling rational design based on desired transitional pH ranges. The structure‐activity relationship of these pH‐responsive peptides was evaluated by assessing their antimicrobial properties, as their antimicrobial activity is triggered by the disassembly of peptides to release active monomers. This approach not only enhances the specificity and controllability of pH responsiveness but also broadens the scope of peptide materials in biomedical and technological applications. 

We report the successful synthesis of monodispersed Cu2S nanocrystals and the subsequent formation of highly ordered nanocrystal superlattices. The synthesis is performed under ambient air conditions using simple experimental setups, making the process both accessible and scalable. By systematically tuning the reaction temperature and duration, we demonstrate precise control over the nanocrystal size, which is crucial in achieving uniformity and monodispersity. Furthermore, we uncover a previously unidentified nanocrystal growth mechanism that plays a key role in producing highly monodisperse Cu2S nanocrystals. This insight into the growth process enhances our fundamental understanding of nanocrystal formation and could be extended to the synthesis of other semiconductor nanomaterials. The self-assembly of these nanocrystals into superlattices is carefully examined using electron diffraction techniques, revealing the presence of pseudo-crystalline structures. The ordered arrangement of nanocrystals within these superlattices suggests strong interparticle interactions and opens up new possibilities to tailor their collective optical, electronic, and mechanical properties for potential applications in optoelectronics, nanomedicine, and energy storage. 

Lithium metal batteries (LMBs) are considered one of the most promising next-generation rechargeable batteries due to their high specific capacity. However, severe dendrite growth and subsequent formation of dead lithium (Li) during the battery cycling process impede its practical application. Although extensive experimental studies have been conducted to investigate the cycling process, and several theoretical models were developed to simulate the Li dendrite growth, there are limited theoretical studies on the dead Li formation, as well as the entire cycling process. Herein, we developed a phase-field model to simulate both electroplating and stripping process in a bare Li anode and Li anode covered with a protective layer. A step function is introduced in the stripping model to capture the dynamics of dead Li. Our simulation clearly shows the growth of dendrites from a bare Li anode during charging. These dendrites detach from the bulk anode during discharging, forming dead Li. Dendrite growth becomes more severe in subsequent cycles due to enhanced surface roughness of the Li anode, resulting in an increasing amount of dead Li. In addition, it is revealed that dendrites with smaller base diameters detach faster at the base and produce more dead lithium. Meanwhile, the Li anode covered with a protective layer cycles smoothly without forming Li dendrite and dead Li. However, if the protective layer is fractured, Li metal preferentially grows into the crack due to enhanced Li-ion (Li+) flux and forms a dendrite structure after penetration through the protective layer, which accelerates the dead Li formation in the subsequent stripping process. Our work thus provides a fundamental understanding of the mechanism of dead Li formation during the charging/discharging process and sheds light on the importance of the protective layer in the prevention of dead Li in LMBs. 

Two distinct ultra-thin Ge1−xSnx (x ≤ 0.1) epilayers were deposited on (001) Si substrates at 457 and 313 °C through remote plasma-enhanced chemical vapor deposition. These films are considered potential initiation layers for synthesizing thick epitaxial GeSn films. The GeSn film deposited at 313 °C has a thickness of 10 nm and exhibits a highly epitaxial continuous structure with its lattice being compressed along the interface plane to coherently match Si without mismatch dislocations. The GeSn film deposited at 457 °C exhibits a discrete epitaxial island-like morphology with a peak height of ∼30 nm and full-width half maximum (FWHM) varying from 20 to 100 nm. GeSn islands with an FWHM smaller than 20 nm are defect free, whereas those exceeding 25 nm encompass nanotwins and/or stacking faults. The GeSn islands form two-dimensional modulated superlattice structures at the interface with Si. The GeSn film deposited at 457 °C possesses a lower Sn content compared to the one deposited at lower temperature. The potential impact of using these two distinct ultra-thin layers as initiation layers for the direct growth of thicker GeSn epitaxial films on (001) Si substrates is discussed.