Temporarily solid, permanently porous
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Advanced 3D printing accelerates electromagnetic wave absorption from ceramic materials to structures
As 3D printing technology and ceramic material advance, significant progress has been achieved in the field of 3D-printed ceramic materials for electromagnetic wave absorption (EMWA), transitioning from simple material fabrication to complex structure creation. This review summarizes the key advancements in ceramic materials and structures fabricated by 3D printing for EMWA. Despite significant progress, the limitations that remain in 3D-printed ceramic materials and structures for EMWA are highlighted, and future development tendencies are also identified. This review aims to motivate further development and application of 3D-printed ceramic materials and structures for EMWA.
Distance-controlled direct ink writing of titanium alloy with enhanced shape diversity and controllable porosity
Porous titanium alloys have been extensively used for diverse engineering applications. However, current additive manufacturing (AM) strategies face significant challenges (e.g., low fabrication efficiency and limited shape diversity) in producing porous titanium alloys. This work aims to develop a distance-controlled direct ink writing (DC-DIW) approach for constructing macroscale 3D architectures from titanium alloy powders. This approach integrates a constant interlayer distance control with traditional DIW, breaking through the angle limit in current porous metal printing from 60° to 30°. Additionally, subsequent heat treatment is applied to control microstructures. To demonstrate the capabilities of this approach, three representative structures, including a bifurcated tube, an orbital implant, and a knee implant, are successfully printed and treated, achieving suitable mechanical properties and high shape fidelity. This work provides a viable and efficient AM strategy for fabricating porous titanium alloys with enhanced shape diversity and controllable porosity suitable for various engineering applications.
Cancer cells sense solid stress to enhance metastasis by CKAP4 phase separation-mediated microtubule branching
Solid stress, originating from rigid and elastic components of extracellular matrix and cells, is a typical physical hallmark of tumors. Mounting evidence indicates that elevated solid stress drives metastasis and affects prognosis. However, the molecular mechanism of how cancer cells sense solid stress, thereby exacerbating malignancy, remains elusive. In this study, our clinical data suggest that elevated stress in metastatic solid tumors is highly associated with the expression of cytoskeleton-associated protein 4 (CKAP4). Intriguingly, CKAP4, as a sensitive intracellular mechanosensor, responds specifically to solid stress in a subset of studied tumor micro-environmental elements through liquid–liquid phase separation. These micron-scaled CKAP4 puncta adhere tightly onto microtubules and dramatically reorchestrate their curvature and branching to enhance cell spreading, which, as a result, boosts cancer cell motility and facilitates distant metastasis in vivo. Mechanistically, the intrinsically disordered region 1 (IDR1) of CKAP4 binds to microtubules, while IDR2 governs phase separation due to the Cav1.2-dependent calcium influx, which collectively remodels microtubules. These findings reveal an unprecedented mechanism of how cancer cells sense solid stress for cancer malignancy and bridge the gap between cancer physics and cancer cell biology.
Developing elastic foamed TPU fibers for dynamically daytime radiative cooling textile with buoyancy function
Porous materials are widely used in various scenarios due to their advantages such as good thermal insulation, flexibility, and ultra-lightness. Foaming technology has given porous materials more application areas by introducing uniformly distributed cellular structures into the polymer collective. In the past decade, we have conducted systematic studies around the preparation of multi-component polymer microporous materials and functional applications of porous materials. In this work, we propose the preparation of foamed TPU fibers and foamed fabrics (FT-fabric) with anisotropic cell structure using TPU as substrate by micro-extrusion foaming techniques. Thanks to the multistage cell distribution of the FT-fabric and the vibrational absorption of the polymer in the MIR band, the prepared FT-fabric has a near-infrared reflectance of >97%, which enables effective radiative cooling. The porous structure of the FT-fabric endows it with an ultra-low density, which is able to provide additional buoyancy in water. As a conceptual demonstration, FT-fabric is able to function as a cooling and buoyancy support in seaside scenarios, among other functions, providing a viable avenue for new functional garments.
Immobility of isolated swarmer cells due to local liquid depletion
Bacterial swarming is a complex phenomenon in which thousands of self-propelled rod-shaped cells move coherently on surfaces, providing a highly studied example of active matter. However, bacterial swarming is different from most studied examples of active systems because single isolated cells do not move, while clusters do. The biophysical aspects underlying this behavior are unclear. In this work we explore the case of low local cell densities, where single cells become temporarily immobile. We show that immobility is related to local depletion of liquid. In addition, it is also associated with the state of the flagella. Specifically, the flagellar bundles at (temporarily) liquid-depleted regions are completely spread-out. Our results suggest that dry models of self-propelled agents, which only consider steric alignments and neglect hydrodynamic and hydration effects, are oversimplified and are not sufficient to describe swarming bacteria.
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