Soft polymer materials, which are similar to human tissues, have played critical roles in modern interdisciplinary research. Compared with conventional methods, 3D printing allows rapid prototyping ...and mass customization and is ideal for processing soft polymer materials. However, 3D printing of soft polymer materials is still in the early stages of development and is facing many challenges including limited printable materials, low printing resolution and speed, and poor functionalities. The present review aims to summarize the ideas to address these challenges. It focuses on three points: 1) how to develop printable materials and make unprintable materials printable, 2) how to choose suitable methods and improve printing resolution, and 3) how to directly construct functional structures/systems with 3D printing. After a brief introduction on this topic, the mainstream 3D printing technologies for printing soft polymer materials are reviewed, with an emphasis on improving printing resolution and speed, choosing suitable printing techniques, developing printable materials, and printing multiple materials. Moreover, the state‐of‐the‐art advancements in multimaterial 3D printing of soft polymer materials are summarized. Furthermore, the revolutions brought about by 3D printing of soft polymer materials for applications similar to biology are highlighted. Finally, viewpoints and future perspectives for this emerging field are discussed.
3D printing of soft polymer materials allows the rapid prototyping of functional soft architectures in a highly integrated way. Herein, the recent advancements in this emerging topic are reviewed based on a target to improve its printing speed, resolution, printable material, and functionalities. The trends of multimaterial 3D printing are discussed and the perspectives for this emerging field are provided.
The high fracture toughness of mollusk nacre is predominantly attributed to the structure‐associated extrinsic mechanisms such as platelet sliding and crack deflection. While the nacre‐mimetic ...structures are widely adopted in artificial ceramics, the extrinsic mechanisms are often weakened by the relatively low tensile strength of the platelets with a large aspect ratio, which makes the fracture toughness of these materials much lower than expected. Here, it is demonstrated that the fracture toughness of artificial nacre materials with high inorganic contents can be improved by residual stress‐induced platelet strengthening, which can catalyze more effective extrinsic toughening mechanisms that are specific to the nacre‐mimetic structures. Thereby, while the absolute fracture toughness of the materials is not comparable with advanced ceramic‐based composites, the toughness amplification factor of the material reaches 16.1 ± 1.1, outperforming the state‐of‐the‐art biomimetic ceramics. The results reveal that, with the merit of nacre‐mimetic structural designs, the overall fracture toughness of the artificial nacre can be improved by the platelet strengthening through extrinsic toughening mechanisms, although the intrinsic fracture toughness may decrease at platelet level due to the strengthening. It is anticipated that advanced structural ceramics with exceeding performance can be fabricated through these unconventional strategies.
This work illustrates an anti‐intuitive strategy that, with the merit of biomimetic designs, residual stress that is conventionally harmful to ceramics can inversely help improve the fracture toughness of biomimetic ceramics through nanoscale residual stress‐induced platelet strengthening. This provides new insights into the design principles of nacre‐like materials at the bottom level.
Liquid‐metal (LM)‐based flexible and stretchable electronics have attracted widespread interest in wearable computing, human–machine interaction, and soft robotics. However, many current examples are ...one‐off prototypes, whereas future implementation requires mass production. To address this critical challenge, an integrated multimaterial 3D printing process composed of direct ink writing (DIW) of sealing silicone elastomer and special LM‐silicone (LMS) inks for manufacturing high‐performance LM‐based flexible and stretchable electronics is presented. The LMS ink is a concentrated mixture of LM microdroplets and silicone elastomer and exhibits excellent printability for DIW printing. Guided by a verified theoretical model, a printing process with high resolution and high speed can be easily implemented. Although LMS is not initially conductive, it can be activated by pressing or freezing. Activated LMS possesses good conductivity and significant electrical response to strain. Owing to LMS's unique structure, LMS‐embedded flexible electronics exhibit great damage mitigation, in that no leaking occurs even when damaged. To demonstrate the flexibility of this process in fabricating LM‐based flexible electronics, multilayer soft circuits, strain sensors, and data gloves are printed and investigated. Notably, utilizing LMS's unique activating property, some functional circuits such as one‐time pressing/freezing‐on switch can be printed without any structural design.
A special liquid‐metal–silicone (LMS) ink and corresponding multimaterial printing process are developed for fabricating all‐printed flexible and stretchable electronics. It exhibits excellent printability and good conductivity, significant electrical response to deformation, and great reliability. Thanks to these, all‐printed flexible electronics with high throughput, resolution, and device reliability can be easily fabricated.
Ultrathick electrode design is a promising strategy to enhance the specific energy of Li‐ion batteries (LIBs) without changing the underlying materials chemistry. However, the low Li‐ion conductivity ...caused by ultralong Li‐ion transport pathway in traditional random microstructured electrode heavily deteriorates the rate performance of ultrathick electrodes. Herein, inspired by the vertical microchannels in natural wood as the highway for water transport, the microstructures of wood are successfully duplicated into ultrathick bulk LiCoO2 (LCO) cathode via a sol–gel process to achieve the high areal capacity and excellent rate capability. The X‐ray‐based microtomography demonstrates that the uniform microchannels are built up throughout the whole wood‐templated LCO cathode bringing in 1.5 times lower of tortuosity and ≈2 times higher of Li‐ion conductivity compared to that of random structured LCO cathode. The fabricated wood‐inspired LCO cathode delivers high areal capacity up to 22.7 mAh cm−2 (five times of the existing electrode) and achieves the dynamic stress test at such high areal capacity for the first time. The reported wood‐inspired design will open a new avenue to adopt natural hierarchical structures to improve the performance of LIBs.
Inspired by the vertical microchannels in natural wood as the highway for water transport, an ultra‐thick bulk LiCoO2 (LCO) cathode with vertical channels is fabricated to enhance the transport of Li+. Remarkably, the fabricated LCO cathode shows low tortuosity and high Li‐ion conductivity, and can deliver high areal capacity up to 22.7 mAh cm−2.
Dysregulated autophagy is associated with many pathological disorders such as cardiovascular diseases. Emerging evidence has suggested that circular RNAs (circRNAs) have important roles in some ...biological processes. However, it remains unclear whether circRNAs participate in the regulation of autophagy. Here we report that a circRNA, termed autophagy-related circular RNA (ACR), represses autophagy and myocardial infarction by targeting Pink1-mediated phosphorylation of FAM65B. ACR attenuates autophagy and cell death in cardiomyocytes. Moreover, ACR protects the heart from ischemia/reperfusion (I/R) injury and reduces myocardial infarct sizes. We identify Pink1 as an ACR target to mediate the function of ACR in cardiomyocyte autophagy. ACR activates Pink1 expression through directly binding to Dnmt3B and blocking Dnmt3B-mediated DNA methylation of Pink1 promoter. Pink1 suppresses autophagy and Pink1 transgenic mice show reduced myocardial infarction sizes. Further, we find that FAM65B is a downstream target of Pink1 and Pink1 phosphorylates FAM65B at serine 46. Phosphorylated FAM65B inhibits autophagy and cell death in the heart. Our findings reveal a novel role for the circRNA in regulating autophagy and ACR-Pink1-FAM65B axis as a regulator of autophagy in the heart will be potential therapeutic targets in treatment of cardiovascular diseases.
Increasing evidence suggests that long noncoding RNAs (lncRNAs) play crucial roles in various biological processes. However, little is known about the effects of lncRNAs on autophagy. Here we report ...that a lncRNA, termed cardiac autophagy inhibitory factor (CAIF), suppresses cardiac autophagy and attenuates myocardial infarction by targeting p53-mediated myocardin transcription. Myocardin expression is upregulated upon H
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and ischemia/reperfusion, and knockdown of myocardin inhibits autophagy and attenuates myocardial infarction. p53 regulates cardiomyocytes autophagy and myocardial ischemia/reperfusion injury by regulating myocardin expression. CAIF directly binds to p53 protein and blocks p53-mediated myocardin transcription, which results in the decrease of myocardin expression. Collectively, our data reveal a novel CAIF-p53-myocardin axis as a critical regulator in cardiomyocyte autophagy, which will be potential therapeutic targets in treatment of defective autophagy-associated cardiovascular diseases.
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•This paper summarized 159 natural compounds against ALI.•The paper summed up the protective effects of all products on ALI in vivo and vitro.•This paper clarified the underlying ...mechanism of natural compounds against ALI.
Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.
Perceptual quality assessment of distorted three-dimensional (3D) images has become a fundamental yet challenging issue in the field of 3D imaging. In this paper, we propose a general-purpose ...blind/no-reference (NR) 3D image quality assessment (IQA) metric that utilizes the complementary local patterns (the local magnitude pattern and the proposed generalized local directional pattern) of binocular energy response (BER) and binocular rivalry response (BRR). The main technical contribution of this research is that binocular visual perception and local structural distribution are considered for NR 3D-IQA. More specifically, the metric simulates the binocular visual perception using BER and BRR. Subsequently, the local patterns of the binocular responses' encoding maps are used to form various binocular quality-predictive features, which will change in the presence of distortions. After feature extraction, we use k-nearest neighbors-based machine learning to drive the overall quality score. We tested our proposed metric against two publicly available 3D databases; these tests confirm that the proposed metric's results consistently align with human subjective judgments.
Lithium metal based anode with hierarchical structure to enable high rate capability, volume change accommodation, and dendritic suppression is highly desirable for all-solid-state lithium metal ...battery. However, the fabrication of hierarchical lithium metal based anode is challenging due to the volatility of lithium. Here, we report that natural diatomite can act as an excellent template for constructing hierarchical silicon-lithium based hybrid anode for high performance all-solid-state lithium metal battery. This hybrid anode exhibits stable lithium stripping/plating performance over 1000 h with average overpotential lower than 100 mV without any short circuit. Moreover, all-solid-state full cell using this lithium metal composite anode to couple with lithium iron phosphate cathode shows excellent cycling stability (0.04% capacity decay rate for 500 cycles at 0.5C) and high rate capability (65 mAh g
at 5C). The present natural diatomite derived hybrid anode could further promote the fabrication of high performance all-solid-state lithium batteries from sustainable natural resources.
Abnormal mitochondrial fission participates in the pathogenesis of many diseases. Long non-coding RNAs (lncRNAs) are emerging as new players in gene regulation, but how lncRNAs operate in the ...regulation of mitochondrial network is unclear. Here we report that a lncRNA, named cardiac apoptosis-related lncRNA (CARL), can suppress mitochondrial fission and apoptosis by targeting miR-539 and PHB2. The results show that PHB2 is able to inhibit mitochondrial fission and apoptosis. miR-539 is responsible for the dysfunction of PHB2 and regulates mitochondrial fission and apoptosis by targeting PHB2. Further, we show that CARL can act as an endogenous miR-539 sponge that regulates PHB2 expression, mitochondrial fission and apoptosis. Our present study reveals a model of mitochondrial fission regulation that is composed of CARL, miR-539 and PHB2. Modulation of their levels may provide a new approach for tackling apoptosis and myocardial infarction.
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