Ultrafine Fibers Research Articles

Controlling the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers via the design of condensed structures

Obtaining lignin-based graphite-like microcrystallites at a relatively low carbonization temperature is still very challenging. In this work, we report a new method based on condensed structures, for regulating graphite-like microcrystalline structures via the incorporation of 4,4′-diphenylmethane diisocyanate (MDI) into the main structure of lignin. The effects of MDI on the thermal properties of lignin and the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers were extensively studied and investigated. The incorporation of MDI decreased the thermal stability of lignin, increased the carbon yield and enhanced the formation of graphite-like microcrystallites, which are beneficial for reducing energy consumption during the preparation of lignin-based carbon fibers. The modified lignin-based ultrafine carbon fibers (M-LCFs) demonstrated satisfactory electrochemical performance, including high specific capacitance, low charge transfer resistance, and good cycle performance. The M-LCFs-3/2 electrode had a specific capacitance of 241.3 F g−1 at a current density of 0.5 A g−1, and a residual ratio of 90.2 % after 2000 charge and discharge cycles. This study provides a new approach to control the graphite-like microcrystalline structure and electrochemical performance while also optimizing the temperature.

Piezoelectric Yield of Single Electrospun Poly(acrylonitrile) Ultrafine Fibers Studied by Piezoresponse Force Microscopy and Numerical Simulations.

Quantitative converse piezoelectric coefficient (d33) mapping of polymer ultrafine fibers of poly(acrylonitrile) (PAN), as well as of poly(vinylidene fluoride) (PVDF) as a reference material, obtained by rotating electrospinning, was carried out by piezoresponse force microscopy in the constant-excitation frequency-modulation mode (CE-FM-PFM). PFM mapping of single fibers reveals their piezoelectric activity and provides information on its distribution along the fiber length. Uniform behavior is typically observed on a length scale of a few micrometers. In some cases, variations with sinusoidal dependence along the fiber are reported, compatibly with a possible twisting around the fiber axis. The observed features of the piezoelectric yield have motivated numerical simulations of the surface displacement in a piezoelectric ultrafine fiber concerned by the electric field generated by biasing of the PFM probe. Uniform alignment of the piezoelectric axis along the fiber would comply with the uniform but strongly variable values observed, and sinusoidal variations were occasionally found on the fibers laying on the conductive substrate. Furthermore, in the latter case, numerical simulations show that the piezoelectric tensor's shear terms should be carefully considered in estimations since they may provide a remarkably different contribution to the overall deformation profile.

Structural properties and barrier performance of low-cost aerogel composites for building insulation

The high cost and weak mechanical properties of silica-based aerogel seriously affect its wide application in the field of building insulation. In this paper, low-cost SiO2 aerogel (WSA) was prepared based on water glass/water system, and the modulation of aerogel network structure was achieved under the dual effect of sodium methylsilicate (SMS) and pH. WSA exhibits extremely low density (∼88.5 kg/m3) and thermal conductivity (0.02114 W/(m·K)) as well as high hydrophobicity (150°). The cost of WSA is 53 % lower compared to atmospheric pressure drying and 21.5 % lower than commercial aerogel. On this basis, rock wool fiber felt (RWF) and ultrafine glass fiber wool felt (UGFW) were modified with WSA. The effect of fiber arrangement on the force-thermal coupling property of WSA@RWF was investigated. Meanwhile, the addition of WSA reduced the volumetric water absorption of RWF by 85.1 % and 91.4 %. Since the sandwich structure, the thermal conductivity of WSA@UGFW can be as low as 0.01168 W/(m·W), which is 44.7 % and 44.4 % lower than that of UGFW and WSA. It features a low density of 45.7 kg/m3 and a high hydrophobicity angle of 155.87°. In addition, the compressive strength of WSA@UGFW is increased by 16.5 times. Therefore, the aerogel materials prepared in this paper have great application potential as fire-proof building insulation materials.

Interlaminar reinforced carbon fiber/epoxy composites by electrospun ultrafine hybrid fibers

The demand for high-strength composites in the aerospace industry is increasing; however, their low-impact resistance poses a danger to aircraft. Consequently, significant attention has been devoted to researching the interlaminar toughening of carbon fiber-epoxy composite laminates, focusing on electrospun fibers due to their high porosity and specific surface area. Our previous work explored the potential of poly(aryl ether nitrile) as an interlaminar toughening option. Nonetheless, these materials exhibited a decline in flexural properties. To address this concern, we developed poly(arylene ether nitrile)-poly(ε-caprolactone) ultrafine hybrid fiber membranes via electrospinning to enhance the interlaminar performance of composite laminates. The interlaminar fracture toughness demonstrated a remarkable improvement of 132.5 %. Additionally, the flexural strength in-creased by at least 12.3 %, while the flexural modulus experienced a minimum in-crease of 17.9 %. The interlaminar shear strength improved by approximately 27%–28 %, and the impact strength increased by 99.2 %. This study demonstrates the significant potential of electrospun hybrid fiber membranes in improving the interlaminar properties of carbon fiber-epoxy composite laminates, con-tributing to developing safer and more durable materials for the aerospace industry.

Fabrication of electrospun ultrafine fibreous membrane and their application in paraben adsorption

Electrospinning provides a simple and versatile method for generating ultrafine fibers from a rich variety of materials that include polymers, composites, and ceramics. Find applications in various fields, including tissue engineering, filter media, reinforcement in nanocomposites, and micro/nano-electro-mechanical systems. In this study the polystyrene fibers in 10%, 20% and 30% (w/v) in THF: DMF solvents were characterized by ATR-FTIR, AFM and SEM. The obtained fibers exhibited a smooth surface with fine structures, emphasizing a ribbon-like morphology with bead-like features within the range of 3 µm to 5 µm in diameter. The aim of this study was to extract the parabens at optimized conditions such as pH, adsorbent dose, contact time and the elution of solvent. To examine the mechanism of adsorption kinetics, the two most commonly used kinetics models (pseudo-first order and pseudo-second order) were employed to test experimental data along with the Morris-Weber diffusion model. The obtained data showed that the maximum sorption efficiency obtained at pH 3.0, adsorbent dose optimized as 10 mg of fiber with time of 24 hours, the methanol was sufficient to elute paraben from fibers met. The experimental data of the adsorption followed by first-order reaction with a mass transfer-controlled diffusion mechanism

Wall-mounted ultrafine hollow fiber membrane module for purification of domestic surface water

The World Health Organization (WHO) estimated that around 844 million people worldwide lack safe drinking water, including 159 million who are dependent only on surface water. Investing in a practical, sustainable, and cost-effective treatment process is indispensable to alleviating the effect of water shortage. Besides water treatment, ultrafiltration (UF) membranes are broadly used in protein fractionation and clarification of fruit juices. The hollow fiber (HF) membrane configuration has a much larger surface area per unit volume, resulting in higher productivity than the flat-sheet membrane. A spinneret was developed with a provision for altering the fiber's inner diameter from 1000 µm to 150 µm and outer dimension from 1500 µm to 350 µm, respectively, using an inbuilt detachable needle arrangement. The ultrathin hollow fiber produced by the indigenously designed spinnerets has a high surface area and packing density, which makes it useful for surface water treatment. A wall-mounted module was designed for direct connection to the tap to obtain a purified water flow of 30–40 liter per hour (LPH) for domestic use, operated with or without electricity. The fabricated ultrafine HF module (ID: 150–200 µm; OD: 350–450 µm) removes complete bacterial contamination and turbidity up to 95–100 %, making the quality of processed water potable. The developed membrane module is durable due to its large membrane area per unit volume, enhancing productivity, high packing density, good fouling resistance, easy handling, and self-supporting structure for backwashing. The present research article paves the way forward to investing in a practical, sustainable, and economical treatment process that is indispensable to alleviating the effect of water shortage.

Antimicrobial activity of geranium (Pelargonium graveolens) essential oil and its encapsulation in carioca bean starch ultrafine fibers by electrospinning

Geranium (Pelargonium graveolens) is known for being an aromatic plant rich in bioactive compounds with antibacterial properties. In this study, geranium essential oil (GEO) was extracted and encapsulated in ultrafine bean starch fibers produced by electrospinning as an antibacterial agent. GEO revealed a composition rich in volatile compounds, including citronellol, cis-geraniol, β-linalool, citronellyl formate, and linalool formate. In its free form, GEO exhibited high antibacterial activity against pathogenic bacteria strains (L. monocytogenes, S. aureus, and E. coli). The bean starch fibers, produced with and without the addition of GEO, were uniform and continuous, with an average diameter ranging from 249 to 373 nm. Confocal analysis indicated a uniform distribution of GEO in the fibers, with a loading capacity of 54.0 %, 42.9 %, and 36.5 % for 20 %, 30 %, and 40 % GEO concentrations, respectively. Remarkably, fibers containing 40 % GEO showed a significant reduction in tested bacteria (L. monocytogenes, S. aureus, and E. coli), suggesting promising applications in preventing losses and extending the shelf life of food through active packaging.

The preparation of polypropylene microfiber yarns via vortex airflow‐assisted melt differential electrospinning

AbstractPolypropylene (PP) yarn possesses the advantages of low density and exceptional mechanical properties. Through electrospinning, fibers of PP yarns can be refined from 10 to 20 μm to an ultrafine level, thereby acquiring an enlarged specific surface area and more functional sites, expanding its application in high‐value areas. Herein, vortex airflow‐assisted polymer melt differential electrospinning was proposed to fabricate PP microfiber yarns. Under the influence of an electrostatic field, molten PP automatically splits into multiple jets that are further stretched and cooled into ultrafine fibers by suction airflow induced by vortex airflow. Subsequently, multiple ultrafine fibers were twisted into PP yarns using the vortex airflow. The effects of voltage, melt feed speed, and air pressure on the PP electrospun yams formation process as well as the morphology and mechanical properties of both the yarn and fibers were investigated. The results showed that the diameter of PP fibers ranged from 3 to 5 μm. The PP microfiber yams exhibited a relatively high mechanical strength of 1.6 cN/tex under conditions of 56 kV voltage, 0.22 g/min feed rate, and 0.3 MPa air pressure. Finally, the woven fabric made from electrospun PP yams demonstrated higher hydrophobicity compared with fabric woven from commercial PP filaments, suggesting potential applications in waterproof fabrics.

Bioceramic modular tissue-engineered bone with rapid vascularization for large bone defects

Tackling large bone defects remains a significant clinical challenge due to the limitations in current treatment strategies. This study presents a modular tissue-engineered bone, achieving rapid vascularization within 14 days and showing significant initial stability after implantation. This innovation is driven by the synergy of high-resolution mono-LCD mask photopolymerization 3D printing, electrospinning technology, and photosensitive gel cell carriers, resulting in a bioceramic-electrospun fiber composite scaffold (BECS) that enhances nutrient permeation and mechanical support. Emphasizing biomimicry, the scaffold incorporates an electrospun ultrafine fiber membrane that simulates the periosteum's microvascular structure, crucial for rapid endothelialization of graft lumens. This membrane acts as an advanced carrier for vascular endothelial growth factor (VEGF), facilitating targeted release that significantly promotes vascular regeneration. Our in vitro and in vivo analyses indicate that immediate vascularization and subsequent osteogenesis significantly enhance blood supply and bone regeneration in defect sites. Notably, the application of Human umbilical cord mesenchymal stem cells (UC-MSCs) within the gelatin methacrylate (GelMA) cell carrier ensures uniform distribution and proliferation, essential for balanced bone regeneration. Demonstrating a 75% increase in vascular network formation and a 60% enhancement in osteocalcin (OCN) expression within the initial four weeks, the scaffold supports both rapid vascularization and osteogenesis. This dual-functional tissue-engineered bone represents a significant advancement for treating large bone defects, with the potential to improve current therapeutic strategies substantially.

Ultrathin SiO2 aerogel papers with hierarchical scale enable high-temperature thermal insulation

Aerogel composites reinforced by fibers have found extensive applications in the field of thermal insulation and energy conservation. However, the composites are hindered by their high infrared radiation transmittance and weak interface adhesion in practical applications. Herein, we designed and prepared a novel thin composite called ‘fiber/whisker/aerogel paper’ (SWAP) with a thickness of less than 1 mm. The SWAP integrated SiC nanowhiskers (SiCnw) as opacifiers and ultrafine SiO2 fibers as reinforcement, fabricated through wet manufacturing and sol-gel process. The ‘fiber/aerogel paper’ (SAP) and SWAP exhibited low thermal conductivity at room temperature, measuring 0.025 W/(m·K) and 0.033 W/(m·K), respectively. Additionally, they exhibited low densities of 0.195 g/cm3 and 0.225 g/cm3, respectively. Notably, SWAP exhibited excellent high-temperature insulation performance, primarily due to its low infrared transmittance (50% at 3 μm). The incorporation of SiCnw and ultrafine SiO2 fibers collectively enhanced the interfacial adhesion with the aerogel matrix even amidst rigorous testing (weight loss less than 3%). SWAP also demonstrated flexibility, high thermal stability, hydrophobicity, and flame resistance. Furthermore, a comprehensive investigation into the performance variations and influencing g factors of the material was conducted under different heat treatment conditions. This research provides guidance for the application of such materials under high temperatures.

Detection and characterization of the Pichia manshurica biofilm on the traditionally produced homemade apple vinegar.

Pichia yeasts are capable of forming biofilms during vinegar production and causing spoilage in various beverages. In addition, there exists a significant likelihood of encountering yeast contamination which can prevent vinegar production. The present study investigates the detection and characterization of the Pichia manshurica (P. manshurica) biofilm on traditionally produced homemade apple vinegar. The unique characteristics of vinegar were analyzed with a focus on the constituent, known as the "mother of vinegar", whose composition is comprised of cellulosic biofilm and acetic acid bacteria, including Gluconobacter oxydans (G. oxydans) Briefly, P. manshurica was isolated from apple vinegar and characterized in terms of the effect of biofilm formation on the surface of the cellulosic film on vinegar production. Microbial identification of vinegar with/without contamination by P. manshurica was analyzed through MALDI-TOF mass spectrometry (MS), and biofilm was characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and crystal violet staining. Accordingly, MS spectrum of isolates was identified as G. oxydans and P. manshurica with a ratio of 2.01 and 1.94, respectively. The FTIR analysis indicated that the peaks within the range of 1150-900 cm-1 revealed a high content of polysaccharide in P. manchuria-contaminated biofilm, which is attributed to the stretching vibration of C-C and C-O bonds. The spectral region from 2921.51 to 2853.71 cm-1 exhibited the characteristic of lipids in bacterial cell walls and membranes. SEM images of bacterial biofilms revealed a three-dimensional network composed of ultrafine fibers with a ribbon-like shape; however, the condensed reticulated structure was observed in contaminated biofilms. The presence of two microbial populations was detected regarding the morphological analysis. Crystal violet staining of contaminated-cellulosic biofilms visualized bacterial and yeast colonization. Concisely, this study emphasizes that the proliferation of Pichia during apple fermentation has the potential to adversely affect the quality of the homemade vinegar, due to its distinct biofilm characteristics.

“Rooting” engineering strategy for construction of highly stable, scalable, size-customized oxidized graphene/PA6 ultrafine fiber composite nanofiltration membranes for water purification

Nanofiltration membranes based on graphene oxide exhibit substantial potential for practical applications in water treatment, poised to lead the next generation of separation technology. It is noteworthy that the prominent hydration interaction among graphene–graphene oxide nanosheets stands as the primary factor influencing its stability. Simultaneously, the absence of suitable graphene substrates presents challenges to its large-scale production. In this study, our initial endeavor involved constructing a graphene-based selective layer on a PA6 substrate using a quasi-“rooting” strategy. The graphene selective layer was anchored onto the surface of PA6 fibers (with a diameter size of up to 190.0 mm and a selective layer thickness of approximately 5.0 µm). Experimental results reveal that the permeability of the hybrid graphene oxide/PA6 fiber composite nanofiltration membrane consistently maintained within the range of 7.7 to 14.9 L m⁻² h⁻¹ bar⁻1, with a remarkable dye molecule removal rate of 99.06 %. Even under challenging operating conditions (such as strong acid, strong alkali, polar solvent, oxidation, and the coexistence of salt ions), its separation performance remained stable. The permeability of composite membranes was retained between 10.6 and 12.7 L m⁻² h⁻¹ bar⁻1, and the rejection rate of CR dye reached 95.0 % under harsh conditions. Furthermore, the stability and anti-fouling performance of the composite membrane were significantly enhanced. Deposits on the membrane surface could be effectively removed through physical wiping and repeated water rinsing, maintaining membrane integrity even after vigorous ultrasonic cleaning (120 min, 950 W). Additionally, after undergoing 20 cycles of rinsing with deionized water and a 30-day soak in an aqueous solution, the PA6 substrate and graphene selective layer exhibited robust adhesion. No shedding was observed, and the dye rejection rate of the composite membrane consistently exceeded 95 %. This perfectly illustrates the exceptional structural stability and separation durability of the prepared separation membrane. Our work contributes fundamental design principles and theoretical insights for practical applications.

Production and Characterization of Bioactive and Antimicrobial Titanium Oxide Surfaces with Silver Nanoparticles and a Poly(lactic Acid) Microfiber Coating

Silver nanoparticles (AgNp) were deposited on highly porous TiO2 surfaces by the dripping of a colloidal AgNp solution to provide antimicrobial activity. Micro-porous TiO2 surfaces were obtained on commercially pure titanium by micro-arc oxidation in an electrolyte containing Ca and P precursors. In addition, as silver can be toxic to cells, these surfaces were uniformly covered with the biocompatible and bioresorbable poly(lactic acid) (PLA) polymer by electrospinning, aiming at promoting a controlled release of silver ions to the medium. The resulting AgNp-containing surfaces were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), and in vitro assays were performed to evaluate their antimicrobial activity and bioactivity. Tests revealed that the surfaces showed antimicrobial activity against Staphylococcus aureus, with better results for the surfaces without PLA. However, all the surfaces presented good biocompatibility in assays with mouse MC3T3-E1 pre-osteoblasts, and greater cell differentiation for the polymer-coated surfaces. Finally, the PLA ultrafine fibers electrospun on the TiO2/AgNp surfaces allowed a controlled release of silver ions in the phosphate-buffered saline (PBS) medium.

Preparation of a flame-retardant waterborne polyurethane with core–shell structure and its application in a fire-resistant microfiber synthetic leather

Flame retardant waterborne polyurethane with core-shell structure was synthesized by encapsulating hexaphenoxycyclophosphazene with WPU, and applied to the preparation of flame retardant ultrafine fiber synthetic leather using a two-step method.

Electrospun nanofibers: building blocks for the repair of bone tissue.

Bone, one of the hardest structures of the body, is the basic constituent of the skeletal system, which gives the shape to the body, provides mechanical support for muscles and soft tissues, and provides movement. Even if there is no damage, bone remodeling is a permanent process to preserve and renew the structural, biochemical, and biomechanical integrity of bone tissue. Apart from the remodeling, bone healing is the highly complicated process of repairing deficiencies of bone tissue by the harmonious operation of osteoblasts, osteocytes, osteoclasts, and bone lining cells. Various materials can be used to both trigger the bone healing process and to provide mechanical support to damaged bone. Nanofiber scaffolds are at the forefront of these types of systems because of their extremely large surface area-to-volume ratio, small pore size, and high porosity. Nanofibers are known to be highly functional systems with the ability to mimic the structure and function of the natural bone matrix, facilitating osteogenesis for cell proliferation and bone regeneration. Electrospinning is an easy and fast method to produce non-woven structures consisting of continuous ultrafine fibers with diameters ranging from micrometers down to nanometers. The simplicity and cost-effectiveness of the electrospinning technique, its ability to use a wide variety of synthetic, natural, and mixed polymers, and the formation of highly porous and continuous fibers are the remarkable features of this method. The importance of nanofiber-based scaffolds in bone tissue regeneration is increasing because of suitable pore size, high porosity, osteoinduction, induction of bone growth with osteoconduction, adaptability to the target area, biodegradation, and appropriate mechanical properties, which are among the main parameters that are important in the design of polymeric bone grafts. The aim of this review is to cast light on the increasing use of nanofiber-based scaffolds in bone tissue regeneration and give an insight about bone regeneration, production techniques of the electrospun nanofibers, and varying formulation parameters in order to reach different drug delivery goals. This review also provides an extensive market research of electrospun nanofibers and an overview on scientific research and patents in the field.

Preparation of AgNPs/oregano essential oil composite film and its antibacterial application in the conservation of paper relics

Electrospinning technology is an innovative method used to synthesize continuous ultra-fine polymer fibers of nanomaterials, offering a mild processing environment that enables the integration of bioactive substances, metal particles, and polymer matrix materials. Notably, silver nanoparticles (AgNPs) exhibit significant and eco-friendly antibacterial properties, as these small-sized metal nanoparticles can penetrate bacterial cells swiftly and induce quick sterilization. Additionally, oregano essential oil (OEO), extracted from natural plants, is an environmentally safe agent with broad-spectrum antibacterial and strong antioxidant properties. In this study, four types of electrospun membranes were prepared: polyacrylonitrile (PAN) nanofiber membranes, oregano essential oil (OEO) nanofiber membranes, silver nanofiber membranes loaded with oregano essential oil (AgNPs/OEO), silver nanofiber membranes (AgNPs). To characterize these membranes, their surface morphology, crystalline phase structures, and functional group characteristics were analyzed. The antibacterial effects of these four membranes on rice paper were then investigated through contact and non-contact experiments.Finally, AgNPs/OEO composite film exhibited excellent antifungal effects againstAspergillus nigeron rice paper under both conditions and was essentially non-invasive to the paper cultural relic’s ontology, offering a new method for the conservation of paper cultural relics.

Hydrophobic sorbents based on ultrathin polymer fibers for trapping oil products

Relevance. Increasing negative effects of hydrocarbon production on aquatic ecosystems and tightening of legislative norms on discharge of oil and oil product contaminated water into marine waters. Among various methods used to remove oil from aqueous solutions the most appropriate one is adsorption method. It is explained by its high degree of purification, safety, availability, manufacturability, universality of application. Synthetic materials based on ultrafine fibers have optimal characteristics for manufacturing sorbents for oil removal on their basis. However, the large-scale application of these materials is limited by their high cost, complexity of manufacturing, which excludes the secondary use of polymers as feedstock. In this regard, there is a growing need for economically and environmentally effective hydrophobic materials for sorptive treatment of aqueous media from oil and petroleum products. Aim. To determine sorption properties of hydrophobic fibrous materials produced via pneumatic formation for use as effective hydrocarbon sorbents for liquidation of oil spills in sea and water treatment on oil production platforms. Objects. Sorbents based on polypropylene and polyethylene terephthalate ultrafine fibers. Methods. Gravimetric, spectral analysis, transmission electron microscopy, gas chromatography. Results. The paper introduces the results of investigation of sorption properties of untreated ultrafine fibers obtained by pneumatic atomization and modified by microwave radiation. The authors have carried out the comparative analysis of water absorption and the influence of contact time and acidity of the medium on the degree of sorption of samples obtained from hydrophobic polymers. Promising application of sorbents based on polypropylene ultrathin fibers for oil products extraction from aqueous media was revealed. It is established that modification reduces water absorption of polypropylene sorbents and leads to an insignificant decrease in sorption properties due to changes in the supramolecular structure of polypropylene fiber samples.

Immediate implantation of ultrafine fiber slow-release system based on cell electrospinning to induce osteogenesis of mesenchymal stem cells.

This study presents the development and evaluation of a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) ultrafine fiber slow-release system for in vivo osteogenic induction of human umbilical cord mesenchymal stem cells (HUCMSCs). Utilizing dual-nozzle and cell electrospinning techniques, the system encapsulates L-ascorbic acid-2-phosphate magnesium (ASP), β-glycerophosphate sodium and dexamethasone (DEX) within the fibers, ensuring sustained osteogenic differentiation. The scaffold's morphology, characterization, hydrophilicity, mechanical properties and cellular behavior were examined. Immediate subcutaneous implantation in rabbits was conducted to observe its ectopic osteogenic induction effect. Successfully fabricated P34HB ultrafine fiber slow-release system. Characterization confirmed the uniform distribution of HUCMSCs and inducing components within the scaffold, with no chemical reactions affecting the active components. In vitro tests showcased a prolonged release of DEX and ASP, while biocompatibility assays highlighted the scaffold's suitability for cellular growth. Alizarin Red, type I collagen, and osteopontin (OPN) staining verified the scaffold's potent osteogenic induction effect on HUCMSCs. Notably, immediate implantation into New Zealand White rabbits led to significant new bone formation within 8 weeks. These findings underscore the system's potential for immediate in vivo implantation without prior in vitro induction, marking a promising advancement in bone tissue engineering.

Ultrathin Aerogel Micro/Nanofiber Membranes with Hierarchical Cellular Architecture for High-Performance Warmth Retention.

A low temperature environment poses significant challenges to the global economy and public health. However, the existing cold-protective materials still struggle with the trade-off between thickness and thermal resistance, resulting in poor thermal-wet comfort and limited personal cold protection performance. Here, a scalable strategy, based on electrospinning and solution casting, is developed to create aerogel micro/nanofiber membranes with a hierarchical cellular architecture by manipulating the phase separation of the charged jets and of the spreading casting solution. The integration of interconnected nanopores (30-60 nm), ultrafine fiber diameter, and high porosity, enables the aerogel micro/nanofiber membranes with lightweight, ultrathin thickness (∼0.5 mm), and superior warmth retention performance with ultralow thermal conductivity of 14.01 mW m-1 K-1. And the resultant membrane with customized semiclosed walls exhibits both striking wind resistance and satisfactory thermal-wet comfort (3.4 °C warmer than the cutting-edge thermal underwear). This work will inspire the design and development of high-performance fibrous materials for thermal management applications.

Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring

HighlightsNovel customized metamaterial gelatin-based conductive film (GCF) was developed to ensure good biocompatibility and biodegradability for implantable bioelectronics integrating monitoring with tissue repair. The metamaterial property demonstrated high conformal with soft tissues to promote the signal-to-noise ratio.The GCF revealed elastic modulus regulated from 20 to 420 kPa and Poisson's ratio from − 0.25 to 0.52. It was fabricated by embedding different 3D printing ultrafine fiber networks with metamaterial design into ultra-low modulus Gelatin methacryloyl hydrogel.