Porous Architecture Research Articles

Miniaturized Hard Carbon Nanofiber Aerogels: From Multiscale Electromagnetic Response Manipulation to Integrated Multifunctional Absorbers

AbstractThe multiscale structural engineering strategy presents a powerful method for tailoring the structural attributes of materials at various levels, enabling the flexible control and manipulation of their electromagnetic properties. Nonetheless, orchestrating the multiscale architecture of polymer‐derived carbon aerogels specifically for microwave absorption poses significant challenges. Herein, aramid‐derived hard carbon nanofiber aerogel microspheres (CNFAMs) featuring a hierarchical skin‐core structure are fabricated through a wet‐spinning technique, combined with reprotonation‐mediated self‐assembly and carbonization processes. The presence of large‐scale voids between neighboring microspheres and the microscale porosity within the microspheres themselves improves impedance matching and promotes microwave reflection and scattering. The distinct graphitic domains and defects serve as pivotal elements for conduction and polarization losses, significantly impacting microwave attenuation. By meticulously tailoring the macroscale dimensions, microscale porous architecture, and nanoscale domains, the optimized CNFAMs demonstrate a remarkable absorption bandwidth of 9.62 GHz at an ultralow filling of 0.97 wt%. Additionally, the implementation of application‐oriented microwave absorption through the innovative integration of polysilsesquioxane‐CNFAMs in a host–guest aerogel is explored. This composite system brings together broadband absorption, superhydrophobicity, thermal insulation, resistance to freezing, and robust tolerance to harsh environments. Such a multifaceted approach is designed to tackle the growing challenges associated with complex electromagnetic environments effectively.

X-ray Microtomography Analysis of Integrated Crop–Livestock Production’s Impact on Soil Pore Architecture

X-ray Microtomography Analysis of Integrated Crop–Livestock Production’s Impact on Soil Pore Architecture

Effect of Pore Architecture of 3D Printed Open Porosity Cellular Structures on Their Resistance to Mechanical Loading: Part I – Experimental Studies

Abstract The development of additive manufacturing (AM) techniques has sparked interest in porous structures that can be customized in terms of size, shape, and arrangement of pores. Porous lattice structure (LS, called also lattice struct) offer superior specific stiffness and strength, making them ideal components for lightweight products with energy absorption and heat transfer capabilities. They find applications in industries such as aerospace, aeronautics, automotive, and bone ingrowth applications. One of the main advantages of additive manufacturing is the freedom of design, control over geometry and architecture, cost and time savings, waste reduction, and product customization. However, the designation of appropriate struct/pore geometry to achieve the desired properties and structure remains a challenge. In this part of the study, five lattice structs with various pore sizes, with two volume fractions for each, and shapes (ellipsoidal, helical, X-shape, trapezoidal, and triangular) were designed and manufactured using selective laser sintering (SLS) additive manufacturing technology. Mechanical properties were tested through uniaxial compression, and the apparent stress-strain curves were analyzed. The results showed that the compression tests revealed both monotonic and non-monotonic stress-strain curves, indicating different compression behaviors among the structures. The helical structure exhibited the highest resistance to compression, while other structures showed similarities in their mechanical properties. In Part II of this study provides a comprehensive analysis of these findings, emphasizing the potential of purpose-designed porous structures for various engineering applications.

A Systematic Review on the Generation of Organic Structures through Additive Manufacturing Techniques.

Additive manufacturing (AM) has emerged as a transformative technology in the fabrication of intricate structures, offering unparalleled adaptability in crafting complex geometries. Particularly noteworthy is its burgeoning significance within the realm of medical prosthetics, owing to its capacity to seamlessly replicate anatomical forms utilizing biocompatible materials. Notably, the fabrication of porous architectures stands as a cornerstone in orthopaedic prosthetic development and bone tissue engineering. Porous constructs crafted via AM exhibit meticulously adjustable pore dimensions, shapes, and porosity levels, thus rendering AM indispensable in their production. This systematic review ventures to furnish a comprehensive examination of extant research endeavours centred on the generation of porous scaffolds through additive manufacturing modalities. Its primary aim is to delineate variances among distinct techniques, materials, and structural typologies employed, with the overarching objective of scrutinizing the cutting-edge methodologies in engineering self-supported stochastic printable porous frameworks via AM, specifically for bone scaffold fabrication. Findings show that most of the structures analysed correspond to lattice structures. However, there is a strong tendency to use organic structures generated by mathematical models and printed using powder bed fusion techniques. However, no work has been found that proposes a self-supporting design for organic structures.

Fabrication of chitin-fibrin hydrogels to construct the 3D artificial extracellular matrix scaffold for vascular regeneration and cardiac tissue engineering.

As the cornerstone of tissue engineering and regeneration medicine research, developing a cost-effective and bionic extracellular matrix (ECM) that can precisely modulate cellular behavior and form functional tissue remains challenging. An artificial ECM combining polysaccharides and fibrillar proteins to mimic the structure and composition of natural ECM provides a promising solution for cardiac tissue regeneration. In this study, we developed a bionic hydrogel scaffold by combining a quaternized β-chitin derivative (QC) and fibrin-matrigel (FM) in different ratios to mimic a natural ECM. We evaluated the stiffness of those composite hydrogels with different mixing ratios and their effects on the growth of human umbilical vein endothelial cells (HUVECs). The optimal hydrogels, QCFM1 hydrogels were further applied to load HUVECs into nude mice for in vivo angiogenesis. Besides, we encapsulated human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) into QCFM hydrogels and employed 3D bioprinting to achieve batch fabrication of human-engineered heart tissue (hEHT). Finally, the myocardial structure and electrophysiological function of hEHT were evaluated by immunofluorescence and optical mapping. Designed artificial ECM has a tunable modulus (220-1380 Pa), which determines the different cellular behavior of HUVECs when encapsulated in these. QCFM1 composite hydrogels with optimal stiffness (800 Pa) and porous architecture were finally identified, which could adapt for in vitro cell spreading and in vivo angiogenesis of HUVECs. Moreover, QCFM1 hydrogels were applied in 3D bioprinting successfully to achieve batch fabrication of both ring-shaped and patch-shaped hEHT. These QCFM1 hydrogels-based hEHTs possess organized sarcomeres and advanced function characteristics comparable to reported hEHTs. The chitin-derived hydrogels are first used for cardiac tissue engineering and achieve the batch fabrication of functionalized artificial myocardium. Specifically, these novel QCFM1 hydrogels provided a reliable and economical choice serving as ideal ECM for application in tissue engineering and regeneration medicine.

The Porous SilMA Hydrogel Scaffolds Carrying Dual-Sensitive Paclitaxel Nanoparticles Promote Neuronal Differentiation for Spinal Cord Injury Repair.

In the intricate pathological milieu post-spinal cord injury (SCI), neural stem cells (NSCs) frequently differentiate into astrocytes rather than neurons, significantly limiting nerve repair. Hence, the utilization of biocompatible hydrogel scaffolds in conjunction with exogenous factors to foster the differentiation of NSCs into neurons has the potential for SCI repair. In this study, we engineered a 3D-printed porous SilMA hydrogel scaffold (SM) supplemented with pH-/temperature-responsive paclitaxel nanoparticles (PTX-NPs). We analyzed the biocompatibility of a specific concentration of PTX-NPs and its effect on NSC differentiation. We also established an SCI model to explore the ability of composite scaffolds for in vivo nerve repair. The physical adsorption of an optimal PTX-NPs dosage can simultaneously achieve pH/temperature-responsive release and commendable biocompatibility, primarily reflected in cell viability, morphology, and proliferation. An appropriate PTX-NPs concentration can steer NSC differentiation towards neurons over astrocytes, a phenomenon that is also efficacious in simulated injury settings. Immunoblotting analysis confirmed that PTX-NPs-induced NSC differentiation occurred via the MAPK/ERK signaling cascade. The repair of hemisected SCI in rats demonstrated that the composite scaffold augmented neuronal regeneration at the injury site, curtailed astrocyte and fibrotic scar production, and enhanced motor function recovery in rat hind limbs. The scaffold's porous architecture serves as a cellular and drug carrier, providing a favorable microenvironment for nerve regeneration. These findings corroborate that this strategy amplifies neuronal expression within the injury milieu, significantly aiding in SCI repair.

3D Nickel–Manganese bimetallic electrocatalysts for an enhanced hydrogen evolution reaction performance in simulated seawater/alkaline natural seawater

In this paper, we report an inexpensive one-step synthesis of self-supported 3D nickel-manganese (NiMn) bimetallic coatings and their application for the hydrogen evolution reaction in simulated seawater (1 M KOH + 0.5 M NaCl) and alkaline natural seawater (1 M KOH + natural seawater). These binary coatings were electrodeposited on a titanium substrate using a facile electrochemical deposition method by a dynamic hydrogen bubble template technique. The as-deposited NiMn coatings with variable Mn amounts produce typical globular and unique porous architecture with abundant pores of different sizes. The activity of these fabricated catalysts towards the hydrogen evolution reaction was investigated by linear sweep voltammetry towards simulated seawater and alkaline natural seawater at different temperatures. The surface morphology and composition of the catalysts were also characterized by scanning electron microscopy and inductively coupled plasma optical emission spectroscopy. The as-prepared NiMn/Ti electrocatalyst, which was electrodeposited using a chemical bath containing Ni2+ and Mn2+ ions with a molar ratio of Ni2+:Mn2+ = 1:5, exhibits excellent hydrogen evolution activity in simulated seawater with an ultra-low overpotential of 64.2 mV to reach a current density of 10 mA cm−2. It is noteworthy that this NiMn/Ti electrocatalyst also achieves a current density of 10 mA cm−2 in alkaline natural seawater with a comparably low overpotential of 79.3 mV. The current densities increase by ca. 1.75–2.35 times with an increase in temperature from 25 °C to 75 °C for hydrogen evolution in both electrolytes. This bimetallic catalyst has shown excellent long-term stability at a constant potential of −0.23 V (vs. RHE) and a constant current density of 10 mA cm−2 for 10 h, which ensures higher durability and robustness for practical application of seawater splitting technology.

Dual crosslinked interpenetrating polymer network-based porous hydrogel membrane for solid-state supercapacitor applications

Hydrogel membranes have emerged as promising candidates for solid-state supercapacitors (SSCs), overcoming limitations associated with traditional liquid electrolytes like leakage, thermal hazards, and flammability. However, single-network hydrogels often suffer from poor mechanical properties, making them inadequate for wearable applications. Herein, solution casting technique is used to develop a novel dual-crosslinked semi-interpenetrating polymer network (semi-IPN) hydrogel membrane through in-situ polymerisation of acrylic acid (AA) in a polyvinyl alcohol (PVA) matrix, followed by doping with KOH solution. By adjusting the composition between PVA and AA, the phase separation pathway is controlled, resulting in a homogeneously distributed porous architecture that enhances ion-conductive pathways. The hydrogel exhibited excellent properties, including high ionic conductivity (174 mS cm−1), considerable tensile strength (5 MPa), and significant elongation at break (460 %). Dielectric studies confirmed its significantly improved capacitive behaviour and low conductivity relaxation characteristics. Additionally, the resulting pseudocapacitor assembled with graphite-silvernanowire-polyaniline based composite electrode demonstrated a high specific capacitance (302 F g−1 at 0.2 A g−1) with outstanding capacity retention (75 % up to 500 cycles). Overall, the incorporation of this novel material provides great potential for high-performance SSC applications.

Highly Compressible, Superabsorbent, and Biocompatible Hybrid Cryogel Constructs Comprising Functionalized Chitosan and St. John's Wort Extract.

Biobased porous hydrogels enriched with phytocompounds-rich herbal extracts have aroused great interest in recent years, especially in healthcare. In this study, new macroporous hybrid cryogel constructs comprising thiourea-containing chitosan (CSTU) derivative and a Hypericum perforatum L. extract (HYPE), commonly known as St John's wort, were prepared by a facile one-pot ice-templating strategy. Benefiting from the strong interactions between the functional groups of the CSTU matrix and those of polyphenols in HYPE, the hybrid cryogels possess excellent liquid absorption capacity, mechanical resilience, antioxidant performance, and a broad spectrum of antibacterial activity simultaneously. Thus, owing to their design, the hybrid constructs exhibit an interconnected porous architecture with the ability to absorb over 33 and 136 times their dry weight, respectively, when contacted with a phosphate buffer solution (pH 7.4) and an acidic aqueous solution (pH 2). These cryogel constructs have extremely high compressive strengths ranging from 839 to 1045 kPa and withstand elevated strains of over 70% without developing fractures. Moreover, the water-swollen hybrid cryogels with the highest HYPE content revealed a complete and instant shape recovery after uniaxial compression. The incorporation of HYPE into CSTU cryogels enabled substantial improvement in scavenging reactive oxygen species and an expanded antibacterial spectrum toward multiple pathogens, including Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and fungi (Candida albicans). Cell viability experiments demonstrated the cytocompatibility of the 3D cryogel constructs, which did not induce changes in the fibroblast morphology. This work showcases a simple and effective strategy to immobilize HYPE extracts on CSTU 3D networks, allowing the development of novel multifunctional platforms with promising potential in hemostasis, wound dressing, and dermal regeneration scaffolds.

Tailoring 3D conductive networks as wearable sensors for pressure or temperature sensing

Wearable and highly sensitive sensors that can detect different stimuli are essential in versatile applications. Despite some progress has been achieved on multi-sensing functions, the construction of flexible pressure and temperature sensors with desirable sensing performances in facile and cost-effective process still remains a challenge. Here, a flexible sensor with conductive porous structure is proposed by simply combining carbon black (CB) and thermoplastic polyurethane (TPU) via sugar-templated pore making strategy. Notably, moderate CB filler amount (30 %) and tunable porous architecture endow the fabricated sensor with satisfactory sensitivity (−3.63 kPa−1), fast response (123 ms), and fascinating recoverability (6000 cycles). In addition to the mechanical stimulus reception, the sensor is demonstrated to possess thermosensitive ability, allowing the real-time capture of the electrical characteristics to temperature change. Furthermore, an integrated sensor array can be realized to detect spatial distribution of pressure/temperature, suggesting the possibility in health-status monitoring, environmental sensing and electronic skin.

Tailored Sugar-Mediated Porous Particle Structures for Improved Dispersion of Drug Nanoparticles in Spray-Freeze-Drying.

We fabricated porous particles incorporating sugars (mannitol, sucrose, or dextran) and fenofibrate nanoparticles (FNPs) by using spray-freeze-drying (SFD). The type of sugar significantly influenced the pore architecture of the resulting SFD particles. Rapid freezing of droplets containing dextran produced ice encapsulation within a dextran matrix, forming porous dextran particles. In the presence of FNPs, the particle size (approximately 4 μm) and pore volume (0.3 cm3/g) of SFD dextran were barely affected. In contrast, SFD particles derived from mannitol and sucrose exhibited denser structures with a lower pore volume than dextran. SFD mannitol incorporating FNPs produced porous structures. FNPs containing surfactant and polymer, which reduced surface tension and increased viscosity, promoted the formation of small droplets with a polymeric structure and porous particles with a relatively sharp size distribution with a median around 5 μm. FNPs were uniformly distributed in SFD dextran, which featured large pore structures, whereas in SFD mannitol, the Raman signal of FNPs was more broadly distributed across the powder samples. Both morphologies contributed to enhancing the FNP dispersibility within a redispersed suspension of SFD particles. FNPs in SFD mannitol and dextran matrices maintained their particle size distribution from before SFD, showing no aggregation upon redispersion. Dextran formed a highly porous network irrespective of the presence of FNPs, whereas mannitol tended to alter the particle attributes upon FNP inclusion. In conclusion, SFD particles derived from dextran and mannitol might help to increase FNP dispersibility by increasing the formation of porous architectures.

3D printing calcium phosphate ceramics with high osteoinductivity through pore architecture optimization

The osteoinductivity of 3D printed calcium phosphate (CaP) ceramics has a large gap compared with those prepared by conventional foaming methods, and improving the osteoinductivity of 3D printing CaP ceramics is crucial for successful application in bone regeneration. Pore architecture plays a critical role in osteoinductivity. In this study, CaP ceramics with a hexagonal close-packed (HCP) spherical pore structure were successfully fabricated using DLP printing technology. Additionally, octahedral (Octahedral), diamond (Diamond), and helical (Gyroid) structures were constructed with similar porosity and macropore diameter. CaP ceramics with the HCP structure exhibited higher compression strength (8.39 ± 1.82 MPa) and lower permeability (6.41 × 10−11 m2) compared to the Octahedral, Diamond, and Gyroid structures. In vitro cellular responses indicated that the macropore architecture strongly influenced the local growth rate of osteoblast-formed cell tissue; cells grew uniformly and formed circular rings in the HCP group. Furthermore, the HCP group promoted the expression of osteogenic genes and proteins more effectively than the other three groups. The outstanding osteoinductivity of the HCP group was confirmed in canine intramuscular implantation studies, where the new bone area reached up to 8.02 ± 1.94 % after a 10-week implantation. Additionally, the HCP group showed effective bone regeneration in repairing femoral condyle defects. Therefore, our findings suggest that 3D printed CaP bioceramics with an HCP structure promote osteoinductivity and can be considered as candidates for personalized precise treatment of bone defects in clinical applications. Statement of significance1. 3D printing BCP ceramics with high osteoinductivity were constructed through pore architecture optimization.2. BCP ceramics with HCP structure exhibited relatively higher mechanical strength and lower permeability than those with Octahedral, Diamond and Gyroid structures.3. BCP ceramics with HCP structure could promote the osteogenic differentiation of MC3T3-E1, and showed the superior in-vivo osteoinductivity and bone regeneration comparing with the other structures.

Advancing Ion Separation: Covalent-Organic-Framework Membranes for Sustainable Energy and Water Applications.

ConspectusMembranes are pivotal in a myriad of energy production processes and modern separation techniques. They are essential in devices for energy generation, facilities for extracting energy elements, and plants for wastewater treatment, each of which hinges on effective ion separation. While biological ion channels show exceptional permeability and selectivity, designing synthetic membranes with defined pore architecture and chemistry on the (sub)nanometer scale has been challenging. Consequently, a typical trade-off emerges: highly permeable membranes often sacrifice selectivity and vice versa. To tackle this dilemma, a comprehensive understanding and modeling of synthetic membranes across various scales is imperative. This lays the foundation for establishing design criteria for advanced membrane materials. Key attributes for such materials encompass appropriately sized pores, a narrow pore size distribution, and finely tuned interactions between desired permeants and the membrane. The advent of covalent-organic-framework (COF) membranes offers promising solutions to the challenges faced by conventional membranes in selective ion separation within the water-energy nexus. COFs are molecular Legos, facilitating the precise integration of small organic structs into extended, porous, crystalline architectures through covalent linkage. This unique molecular architecture allows for precise control over pore sizes, shapes, and distributions within the membrane. Additionally, COFs offer the flexibility to modify their pore spaces with distinct functionalities. This adaptability not only enhances their permeability but also facilitates tailored interactions with specific ions. As a result, COF membranes are positioned as prime candidates to achieve both superior permeability and selectivity in ion separation processes.In this Account, we delineate our endeavors aimed at leveraging the distinctive attributes of COFs to augment ion separation processes, tackling fundamental inquiries while identifying avenues for further exploration. Our strategies for fabricating COF membranes with enhanced ion selectivity encompass the following: (1) crafting (sub)nanoscale ion channels to enhance permselectivity, thereby amplifying energy production; (2) implementing a multivariate (MTV) synthesis method to control charge density within nanochannels, optimizing ion transport efficiency; (3) modifying the pore environment within confined mass transfer channels to establish distinct pathways for ion transport. For each strategy, we expound on its chemical foundations and offer illustrative examples that underscore fundamental principles. Our efforts have culminated in the creation of groundbreaking membrane materials that surpass traditional counterparts, propelling advancements in sustainable energy conversion, waste heat utilization, energy element extraction, and pollutant removal. These innovations are poised to redefine energy systems and industrial wastewater management practices. In conclusion, we outline future research directions and highlight key challenges that need addressing to enhance the ion/molecular recognition capabilities and practical applications of COF membranes. Looking forward, we anticipate ongoing advancements in functionalization and fabrication techniques, leading to enhanced selectivity and permeability, ultimately rivaling the capabilities of biological membranes.

Concurrently boosted oxygen reduction/evolution electrocatalysis over highly loaded CoNi/onion-like carbon hybrid nanosheets

Balancing the bicatalytic activities and stabilities between oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a critical yet challenging task for exploring advanced rechargeable Zinc–air batteries (ZABs). Herein, a hybrid nanosheet catalyst with highly dispersed and densified metallic species is developed to boost the kinetics and stabilities of both ORR and OER concurrently. Through a progressive coordination and pyrolysis approach, we directly prepared highly conductive onion-like carbon (OLC) accommodating dense ORR-active CoNC species and enveloping high-loading OER-active CoNi-synergic structures within a porous lamellar architecture. The resultant CoNi/OLC nanosheet catalyst delivers better ORR and OER activities showcasing a smaller reversible oxygen electrode index (ΔE = Ej10 − E1/2) of 0.71 V, compared to state-of-the-art Pt/C-RuO2 catalysts (0.75 V), Co/amorphous carbon polyhedrons (0.80 V), NiO nanoparticles with higher Ni loading (1.00 V), and most CoNi-based bifunctional catalysts reported so far. The rechargeable ZAB assembled with the developed catalyst achieves a remarkable peak power density of 270.3 mW cm−2 (172 % of that achieved by Pt/C + RuO2) and ultrahigh cycling stability with a negligible increase in voltage gap after 800 h (110 mV increase after 200 h for a Pt/C + RuO2-based battery), standing the top level of those ever reported.

A Brief Review on Microstructure Control of Freeze-casted Porous Alumina during Sintering

Freeze-cast ceramics provide a wide range of applications, including filters, catalyst supports, heat-resistant materials, and biomaterials. The unique porous structure of freeze-cast ceramics offers new perspectives in various fields. However, for the functionality and durability of freeze-cast ceramics, a sufficient mechanical strength of the porous architecture is essential. In the freeze-casting process, the final microstructure is determined during sintering at high temperature through densification and grain growth, highlighting the importance of sintering techniques, which can be originated from sintering strategies in the bulk system. In other words, enhancing densification while suppressing grain growth should be realized by tailoring processing variables and/or materials variables. In this review, we suggest an effective way to control the microstructure by addition of dopants in porous alumina prepared by freeze-casting. The results provide a facile method for microstructure control and provide insight into the selection of promising dopants for better mechanical strength of porous ceramics.

Cellulose Membranes: Synthesis and Applications for Water and Gas Separation and Purification.

Membranes are a selective barrier that allows certain species (molecules and ions) to pass through while blocking others. Some rely on size exclusion, where larger molecules get stuck while smaller ones permeate through. Others use differences in charge or polarity to attract and repel specific species. Membranes can purify air and water by allowing only air and water molecules to pass through, while preventing contaminants such as microorganisms and particles, or to separate a target gas or vapor, such as H2 and CO2, from other gases. The higher the flux and selectivity, the better a material is for membranes. The desirable performance can be tuned through material type (polymers, ceramics, and biobased materials), microstructure (porosity and tortuosity), and surface chemistry. Most membranes are made from plastic from petroleum-based resources, contributing to global climate change and plastic pollution. Cellulose can be an alternative sustainable resource for making renewable membranes. Cellulose exists in plant cell walls as natural fibers, which can be broken down into smaller components such as cellulose fibrils, nanofibrils, nanocrystals, and cellulose macromolecules through mechanical and chemical processing. Membranes made from reassembling these particles and molecules have variable pore architecture, porosity, and separation properties and, therefore, have a wide range of applications in nano-, micro-, and ultrafiltration and forward osmosis. Despite their advantages, cellulose membranes face some challenges. Improving the selectivity of membranes for specific molecules often comes at the expense of permeability. The stability of cellulose membranes in harsh environments or under continuous operation needs further improvement. Research is ongoing to address these challenges and develop advanced cellulose membranes with enhanced performance. This article reviews the microstructures, fabrication methods, and potential applications of cellulose membranes, providing some critical insights into processing-structure-property relationships for current state-of-the-art cellulosic membranes that could be used to improve their performance.

Two birds with one stone: Co/Fe bi-MOFs@PAN nanofiber aerogel films for efficient degradation of organic contaminants and separation of emulsions

The development of materials for effective treatment of complex water is in high demand, but remains challenging. In this study, a multifunctional Co/Fe bi-MOFs decorated polyacrylonitrile nanofiber aerogel film was rationally designed and fabricated using a combination of electrospinning, freeze-drying, and subsequent in-situ hydrothermal methods. The NAF has a hierarchically porous architecture and is capable of degrading dyes and separating oil-in-water emulsions. The results demonstrate that the NAF has outstanding catalytic performance in peroxymonosulfate activation for methylene blue degradation, with a degradation efficiency of above 99.74 % and a reaction rate of 0.0911 min−1 within 40 min. Electron paramagnetic resonance analysis and quenching tests revealed that sulfate radical, hydroxyl radical, singlet oxygen, and superoxide radical are all involved in the degradation of MB and sulfate radical is the major reactive species. Furthermore, the composite NAF can separate oil-in-water emulsions with superior efficiency of above 99.85 % and desirable flux higher than 422 L·m−2·h−1, due to its hierarchically porous architecture and remarkable wettability. The composite NAF displays robust reusability and stability for long-term use. This study demonstrates the benefits of integrating advanced oxidation processes with membrane technology and provides novel perspectives into the evolution of multifunctional materials for complex wastewater treatment.

Characterizing collagen scaffold compliance with native myocardial strains using an ex-vivo cardiac model: The physio-mechanical influence of scaffold architecture and attachment method

Applied to the epicardium in-vivo, regenerative cardiac patches support the ventricular wall, reduce wall stresses, encourage ventricular wall thickening, and improve ventricular function. Scaffold engraftment, however, remains a challenge. After implantation, scaffolds are subject to the complex, time-varying, biomechanical environment of the myocardium. The mechanical capacity of engineered tissue to biomimetically deform and simultaneously support the damaged native tissue is crucial for its efficacy. To date, however, the biomechanical response of engineered tissue applied directly to live myocardium has not been characterized. In this paper, we utilize optical imaging of a Langendorff ex-vivo cardiac model to characterize the native deformation of the epicardium as well as that of attached engineered scaffolds. We utilize digital image correlation, linear strain, and 2D principal strain analysis to assess the mechanical compliance of acellular ice templated collagen scaffolds. Scaffolds had either aligned or isotropic porous architecture and were adhered directly to the live epicardial surface with either sutures or cyanoacrylate glue. We demonstrate that the biomechanical characteristics of native myocardial deformation on the epicardial surface can be reproduced by an ex-vivo cardiac model. Furthermore, we identified that scaffolds with unidirectionally aligned pores adhered with suture fixation most accurately recapitulated the deformation of the native epicardium. Our study contributes a translational characterization methodology to assess the physio-mechanical performance of engineered cardiac tissue and adds to the growing body of evidence showing that anisotropic scaffold architecture improves the functional biomimetic capacity of engineered cardiac tissue. Statement of significanceEngineered cardiac tissue offers potential for myocardial repair, but engraftment remains a challenge. In-vivo, engineered scaffolds are subject to complex biomechanical stresses and the mechanical capacity of scaffolds to biomimetically deform is critical. To date, the biomechanical response of engineered scaffolds applied to live myocardium has not been characterized. In this paper, we utilize optical imaging of an ex-vivo cardiac model to characterize the deformation of the native epicardium and scaffolds attached directly to the heart. Comparing scaffold architecture and fixation method, we demonstrate that sutured scaffolds with anisotropic pores aligned with the native alignment of the superficial myocardium best recapitulate native deformation. Our study contributes a physio-mechanical characterization methodology for cardiac tissue engineering scaffolds.

Chitosan Oligosaccharide Laser Lithograph: A Facile Route to Porous Graphene Electrodes for Flexible On-Chip Microsupercapacitors.

In this study, a convenient chitosan oligosaccharide laser lithograph (COSLL) technology was developed to fabricate laser-induced graphene (LIG) electrodes and flexible on-chip microsupercapacitors (MSCs). With a simple one-step CO2 laser, the pyrolysis of a chitosan oligosaccharide (COS) and in situ welding of the generated LIGs to engineering plastic substrates are achieved simultaneously. The resulting LIG products display a hierarchical porous architecture, excellent electrical conductivity (6.3 Ω sq-1), and superhydrophilic properties, making them ideal electrode materials for MSCs. The pyrolysis-welding coupled mechanism is deeply discussed through cross-sectional analyses and finite element simulations. The MSCs prepared by COSLL exhibit considerable areal capacitance of over 4 mF cm-2, which is comparable to that of the polyimide-LIG-based counterpart. COSLL is also compatible with complementary metal-oxide-semiconductor (CMOS) and micro-electro-mechanical system (MEMS) processes, enabling the fabrication of LIG/Au MSCs with comparable areal capacitance and lower internal resistance. Furthermore, the as-prepared MSCs demonstrate excellent mechanical robustness, long-cycle capability, and ease of series-parallel integration, benefiting their practical application in various scenarios. With the use of eco-friendly biomass carbon source and convenient process flowchart, the COSLL emerges as an attractive method for the fabrication of flexible LIG on-chip MSCs and various other advanced LIG devices.

Ion-selective supramolecular membrane with pH-regulated smart nanochannels for lithium extraction

Tunable gating ion-conducting membranes with high water permeability and precise ion selectivity remain urgently demanded in smart nanofiltration for efficient lithium extraction. Herein, inspired by the filtration function of protein channels, we report a smart and high-performance supramolecular membrane constructed via coordination between quaternary ammonium ligands (m-phenylenediamine/polyethyleneimine) and metal ion center (Cu2+). The pore architecture of the supramolecular membrane is dynamic and can be switched by applying pH stimulus, where coordinated interchain expands when exposed to acidic operating conditions and induces concomitantly reinforced electrostatic exclusion due to enhanced local charge density. The tunable gating regularity enables operando modulation of precise ionic separation in situ. The resulting membrane exhibits significantly enhanced water permeance (19.8 L m−2 h−1·bar−1) and simultaneously promoted Li+/Mg2+ selectivity (RMg2+ = 96.4 %), surpassing typical trade-off between permeability and selectivity at pH 3 condition. This study demonstrates the amazing capability of environmental-responsive regulation of membrane pore-channel structure, and provides inspiration for engineering advanced supramolecular membranes for lithium extraction and beyond.