Shape-morphing structures that can reconfigure their shape to adapt to diverse tasks are highly desirable for intelligent machines in many interdisciplinary fields. Shape memory polymers are one of the most widely used stimuli-responsive materials, especially in 3D/4D printing, for fabricating shape-morphing systems. They typically go through a hot-programming step to obtain the shape-morphing capability, which possesses limited freedom of reconfigurability. Cold-programming, which directly deforms the structure into a temporary shape without increasing the temperature, is simple and more versatile but has stringent requirements on material properties. Here, we introduce grayscale digital light processing (g-DLP) based 3D printing as a simple and effective platform for fabricating shape-morphing structures with cold-programming capabilities. With the multimaterial-like printing capability of g-DLP, we develop heterogeneous hinge modules that can be cold-programmed by simply stretching at room temperature. Different configurations can be encoded during 3D printing with the variable distribution and direction of the modular-designed hinges. The hinge module allows controllable independent morphing enabled by cold programming. By leveraging the multimaterial-like printing capability, multi-shape morphing structures are presented. The g-DLP printing with cold-programming morphing strategy demonstrates enormous potential in the design and fabrication of shape-morphing structures.

Transparent silica glass is one of the most essential materials used in society and industry, owing to its exceptional optical, thermal, and chemical properties. However, glass is extremely difficult to shape, especially into complex and miniaturized structures. Recent advances in three-dimensional (3D) printing have allowed for the creation of glass structures, but these methods involve time-consuming and high-temperature processes. Here, we report a photochemistry-based strategy for making glass structures of micrometer size under mild conditions. Our technique uses a photocurable polydimethylsiloxane resin that is 3D printed into complex structures and converted to silica glass via deep ultraviolet (DUV) irradiation in an ozone environment. The unique DUV-ozone conversion process for silica microstructures is low temperature (~220°C) and fast (<5 hours). The printed silica glass is highly transparent with smooth surface, comparable to commercial fused silica glass. This work enables the creation of arbitrary structures in silica glass through photochemistry and opens opportunities in unexplored territories for glass processing techniques.

Background: Cancer associated fibroblasts (CAFs) can remodel tumor microenvironment by secreting exosomes. This study aimed to investigate the role of exosomes derived from cancer-associated fibroblasts in colorectal cancer (CRC) progression. Methods: Circular RNA (circRNA) array was used to identify differentially expressed circRNAs in exosomes from normal fibroblasts (NFs) and CAFs, and confirmed one differentially expressed circRNA circ_0067557 by real-time PCR. The effect of circ_0067557 on proliferation, metastasis, chemoresistance and apoptosis was verified by wound heal, tranwell, CCK8, sphere-forming and flow cytometry assay. Results: Circ_0067557 expression in exosomes from CAFs was higher than those from NFs. CAF-derived exosomes promoted the proliferation, migration, invasion and chemoresistance of CRC cells while suppressed apoptosis. Silencing of circ_0067557 inhibited malignant phenotypes of CRC cells by targeting Lin28A and Lin28B. Moreover, CAF-derived exosomes enhanced the growth of CRC xenograft tumors. Conclusion: Circ_0067557/Lin28A and Lin28B signal axis may be a potential therapy target for CRC.

The occurrence and progression of tumors can be established through a complex interplay among tumor cells undergoing epithelial-mesenchymal transition (EMT), invasive factors and immune cells. In this study, we employed single-cell RNA sequencing (scRNA-seq) and spatially resolved transcriptomics (ST) to evaluate the pseudotime trajectory and spatial interactive relationship between EMT-invasive malignant tumors and immune cells in primary colorectal cancer (CRC) tissues at different stages (stage I/II and stage III with tumor deposit). Our research characterized the spatiotemporal relationship among different invasive tumor programs by constructing pseudotime endpoint-EMT-invasion tumor programs (EMTPs) located at the edge of ST, utilizing evolution trajectory analysis integrated with EMT-invasion genes. Strikingly, the invasive and expansive process of tumors undergoes remarkable spatial reprogramming of regulatory and immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), regulatory T cells (Treg), and exhausted T cells (Tex). These EMTP-adjacent cell are linked to EMT-related invasion genes, especially the C-X-C motif ligand 1 (CXCL1) and CXCL8 genes that are important for CRC prognosis. Interestingly, the EMTPs in stage I mainly produce an inflammatory margin invasive niche, while the EMTPs in stage III tissues likely produce a hypoxic pre-invasive niche. Our data demonstrate the crucial role of regulatory and immunosuppressive cells in tumor formation and progression of CRC. This study provides a framework to delineate the spatiotemporal invasive niche in CRC samples. Graphical Abstract

The design and engineering of liquid crystal elastomers (LCE) composites for enhanced multifunctionality and responsiveness is highly desired. Here, a hollow LCE (h‐LCE) fiber fabricated via coaxial spinning, enabling the straightforward yet effective creation of functional LCE composites, is reported. Inspired by the fiber‐tubule architecture in skeletal muscles, the hollow fiber features an LCE outer shell for programmable actuation and an inner channel allowing for the integration of a variety of functional media. Thus, the h‐LCE fiber can serve as a versatile platform for multifunctionalities in LCE composites. With this unique design strategy, h‐LCE fibers are fabricated with lengths exceeding 3 meters in the lab with outer and inner diameters as small as 250 mm and 120 µm, respectively. The versatility of these h‐LCE fibers across various applications are further demonstrated, from fast‐response stiffness‐tunable actuators by integrating water flow as triggering media and shape memory polymer (SMP) for enhanced mechanical properties, to electrically driven actuating systems through the incorporation of liquid metal, and actuating light‐guides by combining SMP and PDMS optical fiber. The conception of h‐LCE fiber not only advances the design of multifunctional LCE composites but also paves the way for their application in soft robotics, artificial muscles, and beyond.

In this work, the high-strength Mg–5Zn–2Al–2Sn (ZAT522, in wt%) Mg alloys was obtained at 220 °C and 130 °C by a two-step equal channel angular pressing (ECAP). For each stage, two passes were used. The results showed a remarkable grain refinement after the first stage of ECAP (A2 samples), leading to a fine-grained structure with average size of 1.40 μm. The additional stage (A4 samples) caused further grain refinement to 1.18 μm, and an ultra-fine grain structure (700 nm) appeared in the precipitate-rich region. The grain refinement mechanism for both samples was discussed in detail. To this end, the original extrusion fiber texture evolved into a new strong texture characterized by the base planes tilted toward the ECAP shear plane, with a higher Schmid factor value of 0.34. Compared with the as-extruded alloy, the yield strength of the A2 samples increased from 180 to 245 MPa, which was mainly attributed to the combined effects of grain boundary strengthening and precipitation strengthening. In the case of A4 samples, the dislocation strengthening resulted in a net increase in yield strength to 335 MPa, while the ductility was significantly reduced.