Wearable Safeguarding Leather Composite with Excellent Sensing, Thermal Management, and Electromagnetic Interference Shielding.

This work illustrates a "soft-toughness" coupling design method to integrate the shear stiffening gel (SSG), natural leather, and nonwoven fabrics (NWF) for preparing leather/MXene/SSG/NWF (LMSN) composite with high anti-impact protecting, piezoresistive sensing, electromagnetic interference (EMI) shielding, and human thermal management performance. Owing to the porous fiber structure of the leather, the MXene nanosheets can penetrate leather to construct a stable 3D conductive network; thus both the LM and LMSN composites exhibit superior conductivity, high Joule heating temperature, and an efficient EMI shielding effectiveness. Due to the excellent energy absorption of the SSG, the LMSN composites possess a huge force-buffering (about 65.5%), superior energy dissipation (above 50%), and a high limit penetration velocity of 91 m s-1 , showing extraordinary anti-impact performance. Interestingly, LMSN composites possess an unconventional opposite sensing behavior to piezoresistive sensing (resistance reduction) and impact stimulation (resistance growing), thus they can distinguish the low and high energy stimulus. Ultimately, a soft protective vest with thermal management and impact monitoring performance is further fabricated, and it shows a typical wireless impact-sensing performance. This method is expected to have broad application potential in the next-generation wearable electronic devices for human safeguarding.

Biogenic Copper Selenide Nanoparticles for Near-Infrared Photothermal Therapy Application.

Near-infrared (NIR) photothermal therapy (PTT) is attractive for cancer treatment but is currently restricted by limited availability and insufficient NIR-II photoactivity of photothermal agents, for which artificial nanomaterials are usually used. Here, we report the first use of biogenic nanomaterials for PTT application. A fine-controlled extracellular biosynthesis of copper selenide nanoparticles (bio-Cu2-xSe) by Shewanella oneidensis MR-1 was realized. The resulting bio-Cu2-xSe, with fine sizes (∼35.5 nm) and high product purity, exhibited 76.9% photothermal conversion efficiency under 1064 nm laser irradiation, outperforming almost all the existing counterparts. The protein capping also imparted good biocompatibility to bio-Cu2-xSe to favor a safe PTT application. The in vivo PTT with injected bio-Cu2-xSe in mice (without extraction nor further modification) showed 87% tumor ablation without impairing the normal organisms. Our work not only opens a green route to synthesize the NIR-II photothermal nanomaterial but may also lay a basis for the development of bacteria-nanomaterial hybrid therapy technologies.

Transport Channels of Air Pollutants Affecting the Southern Sichuan Basin Based on Gridded Dispersion Simulation.

Air pollutants suspended in the atmosphere have a large impact on air quality, climate, and human health. As one of the important populated and industrialized regions in China, the Sichuan Basin (SCB) has confronted severe air pollution in recent years. Previous studies have shown that regional transport played a significant role in the formation of regional pollution in the SCB, particularly in the southern basin. Using Yibin and Zigong as representative receptor cities, we further identified the transport channels affecting the southern basin by conducting gridded dispersion simulations. A total of seven channels were identified, including three for cyclonic transport, three through the mountainous areas between the Longquan Mountain and the Huaying Mountain, and one along the Yangtze River. Varying seasonal distributions of their occurrence frequencies were observed. Furthermore, observational evidence for several universal channels was presented during a typical transport case. The transport pathways identified in this study can guide the planning of regional distribution of emission sources and the measures for regional joint prevention and control of air pollution.

A glomerulus chip with spherically twisted cell-laden hollow fibers as glomerular capillary tufts.

Glomerulus-on-a-chip, as a promising alternative for drug nephrotoxicity evaluation, is attracting increasing attention. For glomerulus-on-a-chip, the more biomimetic the chip is, the more convincing the application of the chip is. In this study, we proposed a hollow fiber-based biomimetic glomerulus chip that can regulate filtration in response to blood pressure and hormone levels. On the chip developed here, bundles of hollow fibers were spherically twisted and embedded in designed Bowman's capsules to form spherical glomerular capillary tufts, with podocytes and endotheliocytes cultured on the outer and inner surfaces of the hollow fibers, respectively. We evaluated the morphology of cells, the viability of cells, and the metabolic function of cells in terms of glucose consumption and urea synthesis by comparing the results obtained under fluidic and static conditions, confirmed the barrier function of the endotheliocyte-fiber membrane-podocyte structure by monitoring the diffusion of fluorescein isothiocyanate (FITC)-labeled inulin, albumin and IgG, and, for the first time, achieved on-chip filtration regulation in response to the hormone atrial natriuretic peptide. In addition, the application of the chip in the evaluation of drug nephrotoxicity was also preliminarily demonstrated. This work offers insights into the design of a more physiologically similar glomerulus on a microfluidic chip.

Ultra-Stretchable Spiral Hybrid Conductive Fiber with 500%-Strain Electric Stability and Deformation-Independent Linear Temperature Response.

Stretchable configuration occupies priority in devising flexible conductors used in intelligent electronics and implantable sensors. While most conductive configurations cannot suppress electrical variations against extreme deformation and ignore inherent material characteristics. Herein, a spiral hybrid conductive fiber (SHCF) composed of aramid polymeric matrix and silver nanowires (AgNWs) coating is fabricated through shaping and dipping processes. The homochiral coiled configuration mimicked by plant tendrils not only enables its high elongation (958%), but also generates a superior deformation-insensitive effect to existing stretchable conductors. The resistance of SHCF maintains remarkable stability against extreme strain (500%), impact damage, air exposure (90 days), and cyclic bending (150 000 times). Moreover, the thermal-induced densification of AgNWs on SHCF achieves precise and linear temperature response toward a broad range (-20 to 100 °C). Its sensitivity further manifests high independence to tensile strain (0%-500%), allowing for flexible temperature monitoring of curved objects. Such unique strain-tolerant electrical stability and thermosensation hold broad prospects for SHCF in lossless power transferring and expeditious thermal analysis.

Effects of zinc oxide nanoparticles transformation in sulfur-containing water on its toxicity to microalgae: Physicochemical analysis, photosynthetic efficiency and potential mechanisms.

The environmental transformation of nanomaterials will have a significant impact on their ecotoxicity. Sulfidation process is one of the most important transformation processes in the aquatic environment. Although the sulfidation of ZnO nanoparticles (ZnO NPs) has been previously reported, the transformation characteristics and the relationship between the transformation process and toxicity mechanism to aquatic organisms, especially microalgae, require further study. Therefore, we systematically investigated the transformation properties of ZnO NPs in sulfur-containing water and its impact on the toxicity to microalgae. The results showed that the transformation products of ZnO NPs mainly contained ZnS nanoparticles, and their contents increased with the increase of sulfur-zinc molar ratio in the aqueous solution. After the first week of treatment, the sulfidized ZnO NPs showed less toxicity to microalgae than the pristine ZnO NPs, and interestingly, they exhibited higher toxicity over time. The zinc ions and transformation products played a major role in different treatment periods, resulting in different toxicity. The results of photosynthetic pigments, photosynthetic efficiency, and the relative electron transport rates indicated that the sulfidation process of ZnO NPs had a remarkable influence on algal photosynthesis. These newly acquired results will help us explore the transformation characteristics of ZnO NPs and reasonably assess their potential risks in the aquatic environment.

Vehicle exhausts contribute high near-UV absorption through carbonaceous aerosol during winter in a fast-growing city of Sichuan Basin, China.

Carbonaceous aerosols pose significant climatic impact, however, their sources and respective contribution to light absorption vary and remain poorly understood. In this work, filter-based PM2.5 samples were collected in winter of 2021 at three urban sites in Yibin, a fast-growing city in the south of Sichuan Basin, China. The composition characteristics of PM2.5, light absorption and source of carbonaceous aerosol were analyzed. The city-wide average concentration of PM2.5 was 87.4 ± 31.0 µg/m3 in winter. Carbonaceous aerosol was the most abundant species, accounting for 42.5% of the total PM2.5. Source apportionment results showed that vehicular emission was the main source of PM2.5 during winter, contributing 34.6% to PM2.5. The light absorption of black carbon (BC) and brown carbon (BrC) were derived from a simplified two-component model. We apportioned the light absorption of carbonaceous aerosols to BC and BrC using the Least Squares Linear Regression with optimal angstrom absorption exponent of BC (AAEBC). The average absorption of BC and BrC at 405 nm were 51.6 ± 21.5 Mm-1 and 17.7 ± 8.0 Mm-1, respectively, with mean AAEBC = 0.82 ± 0.02. The contribution of BrC to the absorption of carbonaceous reached 26.1% at 405 nm. Based on the PM2.5 source apportionment and the mass absorption cross-section (MAC) value of BrC at 405 nm, vehicle emission was found to be the dominant source of BrC in winter, contributing up to 56.4%. Therefore, vehicle emissions mitigation should be the primary and an effective way to improve atmospheric visibility in this fast-developing city.

Cell-in-cell structure mediates in-cell killing suppressed by CD44.

Penetration of immune cells into tumor cells was believed to be immune-suppressive via cell-in-cell (CIC) mediated death of the internalized immune cells. We unexpectedly found that CIC formation largely led to the death of the host tumor cells, but not the internalized immune cells, manifesting typical features of death executed by NK cells; we named this "in-cell killing" which displays the efficacy superior to the canonical way of "kiss-killing" from outside. By profiling isogenic cells, CD44 on tumor cells was identified as a negative regulator of "in-cell killing" via inhibiting CIC formation. CD44 functions to antagonize NK cell internalization by reducing N-cadherin-mediated intercellular adhesion and by enhancing Rho GTPase-regulated cellular stiffness as well. Remarkably, antibody-mediated blockade of CD44 signaling potentiated the suppressive effects of NK cells on tumor growth associated with increased heterotypic CIC formation. Together, we identified CIC-mediated "in-cell killing" as a promising strategy for cancer immunotherapy.

Modeling nonalcoholic fatty liver disease on a liver lobule chip with dual blood supply.

Nonalcoholic fatty liver disease (NAFLD) has emerged as a public health concern. To date, the mechanism of NAFLD progression remains unclear, and pharmacological treatment options are scarce. Traditional animal NAFLD models are limited in helping address these problems due to interspecies differences. Liver chips are promising for modeling NAFLD. However, pre-existing liver chips cannot reproduce complex physicochemical microenvironments of the liver effectively; thus, NAFLD modeling based on these chips is incomplete. Herein, we develop a biomimetic liver lobule chip (LC) and then establish a more accurate on-chip NAFLD model. The self-developed LC achieves dual blood supply through the designed hepatic portal vein and hepatic artery and the microtissue cultured on the LC forms multiple structures similar to in vivo liver. Based on the LC, NAFLD is modeled. Steatosis is successfully induced and more importantly, changing lipid zonation in a liver lobule with the progression of NAFLD is demonstrated for the first time on a microfluidic chip. In addition, the application of the induced NAFLD model has been preliminarily demonstrated in the prevention and reversibility of promising drugs. This study provides a promising platform to understand NAFLD progression and identify drugs for treating NAFLD. STATEMENT OF SIGNIFICANCE: Liver chips are promising for modeling nonalcoholic fatty liver disease. However, on-chip replicating liver physicochemical microenvironments is still a challenge. Herein, we developed a liver lobule chip with dual blood supply, achieving self-organized liver microtissue that is similar to in vivo tissue. Based on the chip, we successfully modeled NAFLD under physiologically differentiated nutrient supplies. For the first time, the changing lipid zonation in a single liver lobule with the early-stage progression of NAFLD was demonstrated on a liver chip. This study provides a promising platform for modeling liver-related diseases.

Polyacrylamide/Chitosan-Based Conductive Double Network Hydrogels with Outstanding Electrical and Mechanical Performance at Low Temperatures.

Hydrogel-based electronics have received growing attention because of their great flexibility and stretchability. However, the fabrication of conductive hydrogels with high stretchability, excellent toughness, outstanding sensitivity, and low-temperature stability still remains a great challenge. In this study, a type of conductive hydrogels consisting of a double network (DN) structure is synthesized. The dynamically cross-linked chitosan (CS) and the flexible polyacrylamide network doped with polyaniline constitute the DN through the hydrogen bonds between the hydroxyl, amide, and aniline groups. This type of hydrogels displays excellent mechanical performance, striking conductivity, and remarkable freezing tolerance. The flexible electronic sensors based on the double-network hydrogels demonstrate superior strain sensitivity and linear response on various deformations. Additionally, the good antifreezing property of the hydrogels allows the sensors to exhibit excellent performance at -20 °C.

On-Chip Construction of Liver Lobules with Self-Assembled Perfusable Hepatic Sinusoid Networks.

Although various liver chips have been developed using emerging organ-on-a-chip techniques, it remains an enormous challenge to replicate the liver lobules with self-assembled perfusable hepatic sinusoid networks. Herein we develop a lifelike bionic liver lobule chip (LLC), on which the perfusable hepatic sinusoid networks are achieved using a microflow-guided angiogenesis methodology; additionally, during and after self-assembly, oxygen concentration is regulated to mimic physiologically dissolved levels supplied by actual hepatic arterioles and venules. This liver lobule design thereby produces more bionic liver microstructures, higher metabolic abilities, and longer lasting hepatocyte function than other liver-on-a-chip techniques that are able to deliver. We found that the flow through the unique micropillar design in the cell coculture zone guides the radiating assembly of the hepatic sinusoid, the oxygen concentration affects the morphology of the sinusoid by proliferation, and the oxygen gradient plays a key role in prolonging hepatocyte function. The expected breadth of applications our LLC is suited to is demonstrated by means of preliminarily testing chronic and acute hepatotoxicity of drugs and replicating growth of tumors in situ. This work provides new insights into designing more extensive bionic vascularized liver chips, while achieving longer lasting ex-vivo hepatocyte function.

Multi-scale design of the chela of the hermit crab Coenobita brevimanus.

The chela of the hermit crab protects its body against the attack from predators. Yet, a deep understanding of this mechanical defense is still lacking. Here, we investigate the chela of hermit crab, Coenobita brevimanus, and establish the relationships between the microstructures, chemical compositions and mechanical properties to gain insights into its biomechanical functions. We find that the chela is a multi-layered shell composed of five different layers with distinct features of the microstructures and chemical compositions, conferring different mechanical properties. Especially, an increase of the calcium carbonate content towards the layer furthest from the exterior, unlike the chemical gradients of many crustacean exoskeletons, provides a strong resistance to deformation. Nanoindentation measurements reveal that the overall gradient of the elastic modulus and hardness in the cross-section displays a sandwich profile, i.e., a soft core clamped by two stiff surface layers. Further mechanics modeling demonstrates that the high curvature and stiff innermost sublayer enhance the structural rigidity of the chela. In conjunction with the experimental observations, dynamic finite element analysis maps the time-spatial distribution of principal stress and indicates that fiber bridging might be the major mechanism against crack propagation at microscale. The lessons gained from the study of this multiphase biological composite could provide important insights into the design and fabrication of bioinspired materials for structural applications. STATEMENT OF SIGNIFICANCE: Multiple hierarchical structures have been discovered in a variety of exoskeletons. They are naturally designed to maintain the structural integrity and act as a protective layer for the animals. However, each kind of the hierarchical structures has its unique topology, chemical gradients as well as mechanical properties. We find that the chela is multi-layered shell composed of five different layers with distinct features of the microstructures and chemical compositions, conferring different mechanical properties. Especially, a large amount of helicoidal organic fibrils form highly organized 3D woven matrix in the innermost layer, providing a strong mechanical resistance to avoid catastrophic failure. The overall gradient of the elastic modulus and hardness in the cross-section display a sandwich profile, effectively minimizing the stress concentration and deformation. The lessons gained from the multiscale design strategy of the chela provide important insights into the design and fabrication of bioinspired materials.

Optimized Hierarchical Structure and Chemical Gradients Promote the Biomechanical Functions of the Spike of Mantis Shrimps.

The tail spike of the mantis shrimp is the appendage for counteracting the enemy from behind. Here, we investigate the correlations between the chemical compositions, the microstructures, and the mechanical properties of the spike. We find that the spike is a hollow beam with a varying cross section along the length. The cross section comprises four different layers with distinct features of microstructures and chemical compositions. The local mechanical properties of these layers correlate well with the microstructures and chemical compositions, a combination of which effectively restricts the crack propagation while maximizing the release of strain energy during deformation. Finite element analysis and mechanics modeling demonstrate that the optimized structure of the spike confines the mechanical damage in the region near the tip and prevents catastrophic breakage at the base. Furthermore, we use a 3D printing technique to fabricate multiple hollow cylindrical samples consisting of biomimetic microstructures of the spike and confirm that the combination of the Bouligand structure with radially oriented parallel sheets greatly improves the toughness and strength during compression tests. The multiscale design strategy of the spike revealed here is expected to be of great interest for the development of novel bioinspired materials.

Electroluminescent Fabric Woven by Ultrastretchable Fibers for Arbitrarily Controllable Pattern Display.

Flexible textile displays can be revolutionary for information transmission at any place and any time. Typically, textile displays are fabricated by traditional rigid electronics that sacrifice mechanical flexibility of devices or by flexible electronics that do not have an appropriate choice to arbitrarily control single pixels. This work reports on an electroluminescent fabric woven by ultrastretchable fibers (electroluminescent fibers up to 400% stretch, electrode fibers up to 250% stretch), which can exhibit the pixel-based arbitrarily controllable pattern display by a mobile phone application. To realize ultrastretchability, we made these fibers by encapsulating liquid metals on a polyurethane core (high elasticity). To realize arbitrary control, the design shows a plain-woven structure comprising ZnS-based electroluminescent fibers and perpendicular electrode fibers. The cross-points between the electroluminescent fiber and the electrode fiber form pixels that can be switched on or off independently and can further form the pixel-based arbitrarily controllable pattern display. By doping with different elements, ZnS-based electroluminescent fibers can emit green, blue, or yellow lights. Meanwhile, the fabrication of these fibers employs dip-coating, a scalable manufacturing method without high temperature or vacuum atmosphere. These fabrics show great potential in a wide range of applications such as wearable electronic devices, healthcare, and fashion design.

Multi-scale simulation of early kidney branching morphogenesis.

An important feature of the branch morphogenesis during kidney development is the termination of the tips on the outer surface of a kidney. This feature requires the avoidance of the intersection between the tips and existing ducts inside the kidney. Here, we started from a continuous model and implemented the coarse grained rules into a fast and discrete simulations. The ligand-receptor-based Turing mechanism suggests a repulsion that decreases exponentially with distance between interacting branches, preventing the intersection between neighboring branches. We considered this repulsive effect in numerical simulations and successfully reproduce the key features of the experimentally observed branch morphology for an E15.5 kidney. We examine the similarity of several geometrical parameters between the simulation results and experimental observations. The good agreement between the simulations and experiments suggests that the concentration decay caused by the absorption of glial cell line derived neurotrophic factor might be the key factor to affect the geometry in early kidney development.

Role and dynamics of vacuolar pH during cell-in-cell mediated death.

The nonautonomous cell death by entosis was mediated by the so-called cell-in-cell structures, which were believed to kill the internalized cells by a mechanism dependent on acidified lysosomes. However, the precise values and roles of pH critical for the death of the internalized cells remained undetermined yet. We creatively employed keima, a fluorescent protein that displays different excitation spectra in responding to pH changes, to monitor the pH dynamics of the entotic vacuoles during cell-in-cell mediated death. We found that different cells varied in their basal intracellular pH, and the pH was relatively stable for entotic vacuoles containing live cells, but sharply dropped to a narrow range along with the inner cell death. In contrast, the lipidation of entotic vacuoles by LC3 displayed previously underappreciated complex patterns associated with entotic and apoptotic death, respectively. The pH decline seemed to play distinct roles in the two types of inner cell deaths, where apoptosis is preceded with moderate pH decline while a profound pH decline is likely to be determinate for entotic death. Whereas the cancer cells seemed to be lesser tolerant to acidified environments than noncancerous cells, manipulating vacuolar pH could effectively control inner cell fates and switch the ways whereby inner cell die. Together, this study demonstrated for the first time the pH dynamics of entotic vacuoles that dictate the fates of internalized cells, providing a rationale for tuning cellular pH as a potential way to treat cell-in-cell associated diseases such as cancer.

A Novel Reconstruction Method for Measurement Data Based on MTLS Algorithm.

Reconstruction methods for discrete data, such as the Moving Least Squares (MLS) and Moving Total Least Squares (MTLS), have made a great many achievements with the progress of modern industrial technology. Although the MLS and MTLS have good approximation accuracy, neither of these two approaches are robust model reconstruction methods and the outliers in the data cannot be processed effectively as the construction principle results in distorted local approximation. This paper proposes an improved method that is called the Moving Total Least Trimmed Squares (MTLTS) to achieve more accurate and robust estimations. By applying the Total Least Trimmed Squares (TLTS) method to the orthogonal construction way in the proposed MTLTS, the outliers as well as the random errors of all variables that exist in the measurement data can be effectively suppressed. The results of the numerical simulation and measurement experiment show that the proposed algorithm is superior to the MTLS and MLS method from the perspective of robustness and accuracy.

On-Chip Sonoporation-Based Flow Cytometric Magnetic Labeling.

Tracing magnetically labeled cells with magnetic resonance imaging (MRI) is an emerging and promising approach to uncover in vivo behaviors of cells in cell therapy. Today, existing methods for the magnetic labeling of cells are cumbersome and time-consuming, which has greatly limited the progress of such studies on cell therapy. Thus, in this study, using the flow cytometric loading technology, we develop a sonoporation-based microfluidic chip (i.e., a microfluidic chip integrated with ultrasound; MCU), to achieve the safe, instant, convenient, and continuous magnetic labeling of cells. For the MCU we designed, a suitable group of operating conditions for safely and efficiently loading superparamagnetic iron oxide (SPIO) nanoparticles into DC2.4 cells was identified experimentally. Under the identified operating conditions, the DC2.4 cells could be labeled in approximately 2 min with high viability (94%) and a high labeling quantity of SPIO nanoparticles (19 pg of iron per cell). In addition, the proliferative functions of the cells were also well maintained after labeling. Furthermore, the in vivo imaging ability of the DC2.4 cells labeled using the MCU was verified by injecting the labeled cells into the leg muscle of the C57BL/6 mice. The results show that the excellent imaging outcome can be continuously achieved for 7 days at a density of 106 cells/mL. This work can provide insight for the design of magnetic cell labeling devices and promote the MRI-based study of cell therapies.

The mechanobiology of actin cytoskeletal proteins during cell-cell fusion.

Myosin II and spectrin ß display mechanosensitive accumulations in invasive protrusions during cell-cell fusion of Drosophila myoblasts. The biochemical inhibition and deactivation of these proteins results in significant fusion defects. Yet, a quantitative understanding of how the protrusion geometry and fusion process are linked to these proteins is still lacking. Here we present a quantitative model to interpret the dependence of the protrusion size and the protrusive force on the mechanical properties and microstructures of the actin cytoskeleton and plasma membrane based on a mean-field theory. We build a quantitative linkage between mechanosensitive accumulation of myosin II and fusion pore formation at the tip of the invasive protrusion through local area dilation. The mechanical feedback loop between myosin II and local deformation suggests that myosin II accumulation possibly reduces the energy barrier and the critical radius of fusion pores. We also analyse the effect of spectrin ß on maintaining the proper geometry of the protrusions required for the success of cell-cell fusion.

Self-Assembly of Stable Nanoscale Platelets from Designed Elastin-like Peptide-Collagen-like Peptide Bioconjugates.

The self-assembly of nanostructures from elastin-like (poly)peptide (ELP) containing block copolymers has been a subject of intense investigation over decades. However, short synthetic ELPs have rarely been used due to their high inverse transition temperature; the use of short ELPs has largely been limited to polymer conjugates. Motivated by our previous work which successfully overcame this barrier by simply conjugating short ELPs with a triple-helix-forming collagen-like peptide, in this study, we further extend the ELP library to a series of ELPs equipped with aromatic residues and having sequences as short as four pentapeptide motifs. The resulting elastin-like peptide-collagen-like peptide (ELP-CLP) bioconjugates unexpectedly self-assembled into nanosized platelets likely by forming a bilayer structure. Given the previously demonstrated ability of many other CLP conjugates to target collagens and the potential for encapsulation of hydrophobic drugs in collapsed ELPs, these ELP-CLP nanoplatelets may offer similar opportunities for targeted delivery in biomedical and other arenas.