Fiber Direction Research Articles

Influence of Fiber Direction on the Tribological Behavior of Carbon-Reinforced PEEK at Elevated Temperature for Application in Gas Turbine Engines

Abstract The aerospace industry aims for net-zero greenhouse gas emissions by 2050, requiring gas turbine engines to reduce CO2 emissions. This will impact engine material selection due to harsher operating conditions, limiting traditional metal/alloy use. While fiber-reinforced polymer (FRP) composites are commonly used in the aerospace industry, their use in gas turbine engines is often restricted by the lower operating temperatures of the polymer matrix. However, many studies have demonstrated the tribological potential of FRP in the fan section of the engines, but little attention has been given to the potential of orienting the fibers in the normal (i.e., out-of-plane) direction relative to the wear surface to leverage the anisotropic properties of FRP composites. This study investigates the impact of fiber orientation on the tribological properties of carbon fiber/polyetheretherketone (PEEK) (CF-PEEK) at elevated temperatures. Three CF-PEEK samples with different fiber orientations were selected for this study (parallel, antiparallel, and normal directions), as well as a fourth sample of pure PEEK. Tribological tests were conducted using a ball-on-disk tribometer at an elevated temperature of 200 °C to evaluate wear and friction behavior. The worn surfaces and counterfaces were analyzed using confocal laser scanning microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The findings reveal that CF-PEEK with fibers oriented in the normal direction demonstrates significantly enhanced tribological performance at elevated temperatures, achieving a 95% reduction in the friction coefficient and a 92% decrease in the wear-rate compared to pure PEEK. A wear mechanism has been proposed to explain the superior wear resistance of normally oriented fibers in CF-PEEK, linking it to the development of a fiber-based interface during the run-in phase and the formation of a uniform transfer film.

Large stroke radially oriented MXene composite fiber tensile artificial muscles.

Actuation is normally dramatically enhanced by introducing so much yarn fiber twist that the fiber becomes fully coiled. In contrast, we found that usefully high muscle strokes and contractile work capacities can be obtained for non-twisted MXene (Ti3C2Tx) fibers comprising MXene nanosheets that are stacked in the fiber direction. The MXene fiber artificial muscles are called MFAMs. We obtained MFAMs that have high modulus in both the radial and axial directions by spinning a solution containing MXene nanosheets dispersed in an aqueous cellulose solution. We observed a highly reversible muscle contraction of 21.0% for a temperature increase from 25° to 125°C. The tensile actuation of MFAMs mainly results from reversible hydrogen bond orientation change during heating, which decreases intra-sheet spacing. The MFAMs exhibited fast, stable actuation to multiple temperature-generating stimuli, which increases their applications in smart textiles, robotic arms, and robotic grippers.

Strong high-density composites from wheat straw

Wheat straw represents a promising resource for structural materials due to its inherent strength and availability as an underutilized agricultural by-product. However, structural features such as small diameters and a hollow, low-density design, as well as a hydrophobic, waxy surface layer, hinder conventional processing. We present an approach to overcome these hindrances by engineering delignified and densified straw strands into a mechanically strong unidirectional composite material. Wheat straw split into strands along the fiber direction was subjected to water-based and mild alkaline pre-treatments and subsequently densified. As a result, the average tensile strength and modulus of elasticity of straw strands improved to impressive 466 MPa and 26 GPa, respectively. Simultaneously, chemical changes to the surface enabled better adhesive bonding. The resulting unidirectional straw composites exhibited a flexural strength of 190 MPa and an elastic modulus of 20 GPa, well within the range of established wood and bamboo-based materials.

Chromatin-site-specific accessibility: A microtopography-regulated door into the stem cell fate.

Biomaterials that mimic extracellular matrix topography are crucial in tissue engineering. Previous research indicates that certain biomimetic topography can guide stem cells toward multiple specific lineages. However, the mechanisms by which topographic cues direct stem cell differentiation remain unclear. Here, we demonstrate that microtopography influences nuclear tension in mesenchymal stem cells (MSCs), shaping chromatin accessibility and determining lineage commitment. On aligned substrates, MSCs exhibit high cytoskeletal tension along the fiber direction, creating anisotropic nuclear stress that opens chromatin sites for neurogenic, myogenic, and tenogenic genes via transcription factors like Nuclear receptor TLX (TLX). In contrast, random substrates induce isotropic nuclear stress, promoting chromatin accessibility for osteogenic and chondrogenic genes through Runt-related transcription factors (RUNX). Our findings reveal that aligned and random microtopographies direct site-specific chromatin stretch and lineage-specific gene expression, priming MSCs for distinct lineages. This study introduces a novel framework for understanding how topographic cues govern cell fate in tissue repair and regeneration.

Enhancement of Composite Materials Using 3D Printing Technology

With the development of 3D printed composite materials the methods of increasing their mechanical and thermal performance, functionality and properties has become more diverse. Specifically, the focus of this research is on methods of improving the performance of the composite materials through the alteration of the 3D printing parameters including part thickness, fiber direction and density of layers. Continuous fiber reinforcements and hybrid materials have been discussed to overcome issues with anisotropy and the variation of reinforcements density. The findings highlighted here include enhanced tensile strength, thermal stability and the weight-to-strength ratios making the product suitable for aerospace, automotive and health care industries. Challenges such as length scales and dispersion of reinforcements are presented, followed by prospects for further studies in terms of developing multifunctional composites and mass production.

Effect of fiber breakage defect and waviness defect on compressive fatigue behavior and damage evolution of 3D multiaxial braided composites

This paper reports the effects of fiber breakage defects and waviness defects on the compressive fatigue behavior and the progressive damage evolution process of 3D Multiaxial Braided Composites (3DMBCs). Combined with finite element compression simulation and ultra-depth microscope, the internal defect content of composites with different braiding angles was determined. The results demonstrate that the weakening effect of waviness and fiber breakage defects is greater than the strengthening effect of the braiding angle. This causes the fatigue resistance of 3DMBCs with the 31° braiding angle being better in both directions of 0° and 90°. The increase of 4° waviness and 10% fiber breakage defect results in the average fatigue life of composites being shortened by 48% and the energy consumption rate increased by 10% at 85% stress level in the 90° compression direction. The alteration in loading direction modifies the included angle corresponding to the stress component. The stress component parallel to the fiber direction under compressive fatigue load leads to interfacial debonding in the composites, whereas the stress component perpendicular to the fiber direction results in pronounced shear failure.

Considering the Bottom Edge Cutting Effect of the Carbon Fiber Reinforced Polymer Milling Force Prediction Model and Optimization of Machining Parameters.

The milling force plays a pivotal role in CFRP milling. Modeling of the milling force is helpful to explore the changing law, optimize the processing parameters, and then reduce the appearance of defects. However, most of the existing models ignore the effect of the bottom edge. In this paper, the prediction of milling force in CFRP milling processes is taken as the research object. By analyzing the milling mechanism and considering the end milling cutter's bottom cutting edge, the prediction model of milling force was established. Based on the experimental data and simulation data of milling force, the milling force coefficient was obtained by inverse calculation. Subsequently, the predicted cutting force was compared with the experimental cutting force, showing a maximum error of 14.5%, which is within a reasonable range, and the correctness of the model was verified. Furthermore, combined with the delamination damage and the milling force prediction model, a multi-objective optimization model of milling parameters was established, and the genetic algorithm was used to solve the model. The unidirectional carbon fiber plate with a fiber direction angle of 45° was selected as the optimization example. The minimum delamination damage was obtained under the cutting conditions of a spindle speed of 4903.1569 r/min, feed rate per tooth of 0.01 mm/z, and an axial depth of cut of 0.5 mm, and the experimental verification was carried out. The feasibility of the genetic algorithm in CFRP milling parameter optimization modeling was also verified.

Investigation of mechanical properties of multi-walled carbon nanotubes/hollow glass microspheres – carbon fibre-reinforced epoxy composites in transverse fibre directions

Investigation of mechanical properties of multi-walled carbon nanotubes/hollow glass microspheres – carbon fibre-reinforced epoxy composites in transverse fibre directions

WOODEN MATERIALS USED IN LANDSCAPE APPLICATION IN CRAIOVA CITY

During the history, wood materials have become an indispensable material for human life. (Amati M. 2016). Wood is a material compatible with nature, compatible with other building materials such stone, glasses, offering different texture. (Ahern J. 2007). Wood is one of the materials with best respond to the functions of urban green spaces. First of all, it integrates best, from an aesthetic point of view, alongside stone in urban landscaping projects. (Aybike Ayfer KARADAĞ et al. 2017).Since wood is a natural product, its dimension is limited in that its fibrous structural capacity to bear weight varies according to the fiber direction. Despite its widespread use, it had not been used in multi-storey and wide-span structures to the extent of reinforced concrete and steel structures commonly built after the industrial revolution. (Daniel K, Ternaux E. Materiology. 2009)

Infant skull fractures align with the direction of bone mineralization.

The geometry and mechanical properties of infant skull bones differ significantly from those of adults. Over the past decades, debates surrounding whether fractures in infants come from deliberate abuse or accidents have generated significant impacts in both legal and societal contexts. However, the etiology of infant skull fractures remains unclear, which motivates this study with two main components of work. Firstly, we present and implement a progressive unidirectional fabric composite damage model for infant cranial vaults to represent ductile and anisotropic properties-two typical mechanical characteristics of infant skulls. Secondly, we hypothesize that these intrinsic material properties cause injuries perpendicular to the fiber direction to dominate infant skull fractures, resulting in fracture lines that align with the direction of mineralization in the infant skull. The material model and the finite element (FE) model were verified hierarchically, and this hypothesis was verified by reconstructing two legal cases with known fall heights and implementing the above damage model into CT-based subject-specific infant FE head models. We discovered that the infant skull is more susceptible to injuries within planes perpendicular to the mineralization direction because of the anisotropic mechanical property caused by the direction of mineralization, leading to infant skull fractures aligning with the mineralization direction. Our findings corroborated the several previously reported observations of fractures on cranial vaults, demonstrating that these fractures were closely associated with sutures and oriented along the mineralization direction, and revealed the underlying mechanisms of infant skull fracture pattern. The modeling methods and results of this study will serve as an anchor point for more rigorous investigations of infant skull fractures, ultimately aiming to provide convincing biomechanical evidence to aid forensic diagnoses of abusive head trauma.

High Performance of Anion Exchange Membrane Fuel Cells By Introducing Hydrophobic Carbon Nanotube Diffusion Layer

In recent years, anion exchange membrane fuel cells have garnered significant attention due to their ability to utilize low platinum group metal catalysts, thereby reducing manufacturing costs. In contrast to proton exchange membrane fuel cells, anion exchange membrane fuel cells have a distinctive operational characteristic where they produce water at the anode electrode while consuming water on the cathode electrode. The primary challenge hindering their advancement is managing water, specifically addressing the uneven distribution of water between the anode and cathode. As one of the crucial components of the fuel cell, the gas diffusion layer conducts electrons from the catalytic layer to the bipolar plate, transports reaction gases to the catalytic layer for electrochemical reactions, and removes excess water and waste heat generated on the anode electrode. Carbon nanotubes have high specific surface area, superior electrical conductivity, excellent mechanical properties, and inherent hydrophobicity due to their high degree of graphitization, and are considered to be promising materials for optimizing mass transport within gas diffusion layers. Abundant carbon nanotubes are synthesized in situ on carbon fibers to create a three-dimensional network structure, which not only provides more attachment sites for catalytic particles but also facilitates the electron flow path by interlacing carbon nanotubes within the catalytic layer.In this work, the iron-cobalt catalyst was uniformly sprayed onto the gas diffusion substrate through ultrasonic spraying technology. The carbon source atmosphere was ionized and deposited under plasma radio frequency to synthesize abundant carbon nanotubes in the radial direction of the carbon fibers. Contact angle measurements revealed that the carbon nanotube-modified gas diffusion layer exhibited an approximate contact angle of 145°, which was significantly greater than that of the commercial gas diffusion media. Experimental research results indicated that, under various lower relative humidity conditions, when the cathode and anode inlet flow rates were set at 0.3 L/min and 0.5 L/min, respectively, the peak power generated by the membrane electrode assembled with the carbon nanotube-modified gas diffusion layer reached 988.9 mW/cm². This represents a substantial 27.1% increase compared to the performance achieved using the commercial gas diffusion layer. Upon further increasing the cathode and anode inlet flow rates to 0.6 L/min and 1 L/min, respectively, and operating under different higher relative humidity conditions, the membrane electrode assembled with the carbon nanotube-modified gas diffusion layer exhibited a peak power of 1031.7 mW/cm². In stark contrast, the commercial gas diffusion layer achieved only 760.6 mW/cm² under similar conditions. Through equivalent circuit and electrochemical impedance test analysis, it can be seen that the carbon nanotube-modified gas diffusion layer can effectively improve concentration polarization loss and ohmic polarization loss.

Comparative study of toughness and energy evaluation of laminated bamboo composites and toughening mechanism

As toughness becomes an important mechanical property of construction materials, scientific toughness assessment is vital to the development of new materials and helpful for material innovation. For laminated bamboo composites in which the failure modes are relatively uncertain, different methods were applied to evaluate the toughness of bamboo laminate. A comparative study of various toughness evaluation methods was conducted for laminated bamboo. The meaning and error of the toughness expressed by the energy release rate or J-integral determined by different methods were interpreted and analyzed. Based on the calculated toughness, the toughening mechanism of bidirectional laminated bamboo was explored. The results show that the ratio of transverse bamboo strip volume Vf vertical to the initial notch direction has a positive impact on the initial stiffness, maximum load, and energy release rate. Besides that, the layup or arrangement of bamboo strips would also affect the mechanical properties and fracture toughness of laminated bamboo, of which the effect is investigated by dividing the fracture parameters by Vf. It is concluded that the major mechanism for increasing the ductility and the toughness before the maximum load (expressed by D2/D1 and GIcun/Vf or GIc0.8d/Vf) is the crack deflection caused by the hierarchical structure composed of vascular bundles (fiber) and parenchyma tissue (matrix) in a single layer of bamboo laminae. However, the ductility and the toughness after the maximum load (expressed by D3/D2 and GIc0.8d/GIcun) are mainly enhanced by the alternatively arranged bamboo laminae of different fiber directions.

Anisotropic hydrogel sensors with muscle-like structures based on high-absorbent alginate fibers

Hydrogel sensors have attracted much attention as they play a critical role in health monitoring, multifunctional electronic skin, and human-machine interfaces. However, the isotropic structure makes existing hydrogel sensors exhibit isotropic sensing performance. Therefore, it is a challenge to fabricate hydrogels with human tissue-like structures to achieve anisotropic sensing performance. Herein, we proposed a novel method to prepare anisotropic hydrogel sensors using high-absorbent alginate fibers. The anisotropic hydrogel, HAFG@CNTs, was prepared by adsorbing carbon nanotubes on high-absorbent alginate fibers and immobilized using polyacrylamide bonds. The hydrogel had anisotropic mechanical properties and anisotropic ionic conductivity. The modulus and toughness in the parallel fiber direction were 2.31 and 3.75 times higher than those in the perpendicular fiber direction, respectively, and the sensitivity of the parallel fiber direction was higher than that of the vertical direction when strain occurred. In addition, machine learning algorithms were used to predict and classify different action signals obtained from HAFG@CNTs with an accuracy of up to 98.18 %. These advantages offer great potential for applying HAFG@CNTs to wearable devices and medical monitoring.

Abstract 4136863: Diffuse Functional and Structural Abnormalities in Fibrosis: Potential Structural Basis for Sustaining Atrial Fibrillation

Background: Structural remodeling is associated with atrial fibrillation (AF), but detailed structural and functional characteristics is not well defined. Goal: Using a novel transgenic goat model with cardiac-specific overexpression of TGF-β1 leading to increased cardiac fibrosis, we evaluated detailed structural and functional differences between fibrotic and healthy regions of the atria. Methods: Ex-vivo MRI and histology were used to evaluate fibrosis, fiber disarray, and structural anisotropy. Ex-vivo MRI intensity values were scaled to standard deviations around the mean. The functional analysis examined conduction speeds and direction heterogeneity. Conduction anisotropy was measured along the fiber direction obtained with diffusion tensor imaging. Results: The transgenic goats (n=12) had, on average, 21% of the left atria labeled as fibrotic determined from ex-vivo MRI. The histology samples taken from the labeled fibrotic regions had an increase in fibrosis percentage compared to labeled healthy regions (7.78±3.76% vs 2.80±1.86%, p<0.01). The structural anisotropy was lower in fibrotic regions (0.196±0.002 vs 0.244±0.002, p<0.01). Fiber disarray was greater in the fibrotic regions (20.3±0.2° vs 19.2±0.1°, p<0.01). The fibrotic regions had slower conduction speeds (0.78±0.02 m/s vs 1.12±0.02 m/s, p<0.01) and more aligned conduction directions (30.5±0.2° vs 31.6±0.1°, p<0.01), potentially developing unidirectional conduction block. Conduction anisotropy, measured on the fiber directions, was found to be lower in the fibrotic regions (1.86±0.05 vs 2.10±0.02, p=0.04). As scaled MRI intensity increased, the conduction speed, heterogeneity, and anisotropy all decreased. Conclusions: Functional and structural differences exist between fibrotic and healthy regions of the atria. Though statistically significant, the changes are not discrete. The correlation showed gradual functional abnormalities with MRI intensities. Fibrotic regions tended to have increased fiber disarray, slower conduction, and more unidirectional propagation with lower conduction and structural anisotropy. Diffuse functional and structural abnormalities may allow fibrotic regions to serve as a substrate to sustain AF.

Creep evaluation for fiber-reinforced composites with hybrid fibers: From quantifying fiber anchorage effect to homogenization model

A general micromechanical creep model for fiber-reinforced composites with multi-type hybrid fibers is proposed from quantifying the fiber anchorage effects. An average Eshelby tensor-based homogenization method is employed to calculate the effective creep of composites with realistic-shaped (straight, hooked, and wavy) fibers. A fiber anchorage zone is introduced to depict the anchorage effects of fibers and its parameters are obtained by back analysis. The micromechanical model and fiber anchorage zones are validated by comparing with extensive creep experimental data and finite element simulation. According to the micromechanical model, the effects of fiber shapes, types, direction, anchorage zone, and fiber doping on the creep of composites are systematically explored. The results show fiber shapes and types have obvious effects on composites creep. Fiber deflection angle leads to a monotonous increase in creep. The creep with fiber doping is between the two cases without fiber doping. It indicates that the creep of fiber-reinforced composites can be tailored via proper design for these factors.

Diffuse functional and structural abnormalities in fibrosis: Potential structural basis for sustaining atrial fibrillation

BackgroundStructural remodeling has been associated with increased incidence of atrial fibrillation, but how fibrotic regions allow atrial fibrillation to be sustained remains unclear. ObjectiveWith a novel transgenic goat model, we evaluated structural and functional differences between structurally remodeled and healthy regions of the atria. MethodsA novel transgenic goat model with cardiac-specific overexpression of transforming growth factor β1 was used. Ex vivo cardiac magnetic resonance imaging and histology were used to evaluate differences in fibrosis, fiber disarray, and structural anisotropy. Functional analysis examined conduction speeds and direction heterogeneity. By use of underlying fiber orientation obtained with diffusion tensor imaging, conduction anisotropy was calculated. ResultsThe transgenic goats had on average 21% of the left atria labeled fibrotic, determined from ex vivo cardiac magnetic resonance imaging. The histology samples within the labeled fibrotic regions showed an increase in fibrosis percentage. Fractional anisotropy, a measurement of structural anisotropy, was lower, whereas fiber direction heterogeneity, a measurement of the angle difference of the fiber from its neighbors, was greater, indicating increased fiber disarray in fibrotic regions. The fibrotic regions had slower conduction speeds and more aligned conduction directions, potentially allowing unidirectional conduction block to develop. Conduction anisotropy, measured on the underlying fiber directions, was found to be lower in the fibrotic regions. ConclusionFibrotic regions had slower conduction, and propagation tended to flow more unidirectionally. The direction of propagation differs from the underlying fiber direction, leading to lower conduction anisotropy. Functional and structural abnormalities of the fibrotic tissue may allow fibrotic regions to serve as a substrate for an arrhythmia to develop and to be sustained.

Clinical Outcomes and Applicability of Serratus Anterior Muscle Flap With Split Thickness Skin Graft in Thin Resurfacing Reconstructive Surgeries: A Retrospective Analysis.

This retrospective study evaluates the efficacy of the serratus anterior muscle (SAm) free flap combined with a split thickness skin graft (STSG) for thin resurfacing in reconstructive surgery, presenting an alternative to pure skin perforator flaps. It analyzes 14 SAm free flap procedures performed between January 2015 and December 2023. The study cohort comprised 5 women and 9 men, aged 31-80 years, addressing defects caused by infection, malignancy, burn, and trauma, located in various body parts.The study involves harvesting the SAm flap while focusing on anatomical features such as the distinct direction of muscle fibers and the surface location of the vascular pedicle for efficient dissection. It emphasizes the anatomical advantages of the SAm flap, such as robust vascular supply, controlled flap thickness, and preservation of the long thoracic nerve, making it suitable for a range of surgical needs. Complications included STSG loss, partial necrosis, and infection, all managed effectively. Postoperative shoulder function assessment showed no significant impairment.Results demonstrated the successful application of the SAm flap in all cases, with an average flap dimension of 38.21 cm2 and pedicle length of 7.3 cm. The average operation time was 122.1 minutes. The study underscores the SAm flap's adaptability, versatility, and minimal donor site morbidity.It concludes that the SAm flap, in conjunction with STSG, is a viable alternative for thin resurfacing in reconstructive surgery. However, limitations such as the small sample size and procedural variability suggest the need for further research to fully establish the flap's potential in diverse surgical contexts.

Lower limb interosseous membrane in foetuses.

The leg interosseous membrane (LIM) stabilises the tibia and the fibula. These two bones articulate at the proximal and distal tibiofibular joints. In addition, the LIM is the place of attachment of tibialis anterior muscle, extensor digitorum longus muscle, fibularis tertius muscle (anatomical variant), tibialis posterior muscle and flexor hallucis longus muscle. The specific structure of the collagen fibre network of the LIM provides durability comprising collagenous fibres that are predominately projected longitudinally, obliquely, and often transversely. 222 human foetuses (Male: 120, Female: 102) between 117 and 197 (median 177) days of foetal life were available for the study. The material derived from the foetal collection is stored in the Department of Human Morphology and Embryology, Division of Anatomy of the Medical University of Wroclaw. In this study, we assessed the variability of the foetal LIM using a novel dyeing technique to identify the LIM syndesmotic structure. Overall, the study of the three types of interosseous fibres (transverse, oblique, longitudinal) of the right/left leg revealed that the fibres run in all three directions with frequencies approximating 60-70%. However, there were differences in the frequency of fibre directions and in the size of LIM between sexes. After consideration of the directions and size of fibres of LIM, parts of it can be used for reconstruction of the upper limb interosseous membrane. Sexually dimorphic features of the LIM in the studied material confirm the different dynamics of lower limb growth in each sex.

Characterization of early fatigue damage in CFRP unidirectional laminates based on Micro‐CT

AbstractFatigue damages of Carbon Fiber Reinforced Polymer (CFRP) laminates are not obvious. Obtaining the evolution of the internal fatigue damage in CFRP laminates before visible cracks occur is of vital importance for ensuring structural reliability. Micro X‐ray computed tomography (Micro‐CT) can provide micron scale nondestructive imaging of internal structure of materials. In this paper, a preliminary study was conducted on the early fatigue damage evolution of 0° UD laminates. Axial tension‐tension fatigue tests of [0]16 CFRP laminates were carried out, and the evolutionary behavior of damages was confirmed by fatigue dissipated energy. Then, the internal damages of fatigued specimens were observed and reconstructed using Micro‐CT, and statistical parameters such as damage sphericity, length and angle were calculated. The spatial distribution characteristics of cracks were further acquired by surface porosity and frequency distribution of damage positions in ROI. Early damages from tensile‐tensile fatigue in 0° UD laminates extend along the fiber direction with original defects in the interlayer resin enrichment areas as the nucleus, and tend to concentrate near the width edge of the specimens. Finally, a “sandwich” structural model was developed to analyze the internal stresses of laminates under the influence of interlayer resin enrichment. The FEA results revealed that the internal stresses σy and σz concentrate near the width edges of the specimen, resulting in cracks tend to evolve more in the regions close to edges.Highlights Imaging matrix cracks of specimens by Micro‐CT at 12.91 μm voxel size. Demonstrating evolution patterns of cracks with its morphology statistics. Revealing crack distributions in ROIs with variations of surface porosity. Analyzing internal stress distribution by “sandwich” model created from reality.

Electrospinning Aligned SF/Magnetic Nanoparticles-Blend Nanofiber Scaffolds for Inducing Skeletal Myoblast Alignment and Differentiation.

In the realm of skeletal muscle tissue engineering, anisotropic materials that emulate natural tissues show substantial promise. Electrospun scaffolds, mimicking the fibrillar structure of the extracellular matrix, are commonly employed but often fall short in achieving optimal alignment and mechanical strength. Silk fibroin has emerged as a versatile material in tissue engineering, valued for its biocompatibility, mechanical robustness, and biodegradability. However, conventional electrospinning methods of SF result in randomly oriented fibers, limiting their efficacy. In this work, we developed a straightforward method to fabricate directional tissue scaffolds using silk fibroin. By integrating a magnetic field collecting device and incorporating Fe3O4 nanoparticles into the spinning solution, we successfully produced well-aligned silk nanofiber scaffolds. These aligned fibers not only improved scaffold orientation and mechanical properties but also exhibited magnetic responsiveness. The aligned SF scaffolds effectively guided the adhesion, proliferation, and differentiation of mesenchymal stem cells along the fiber direction. Cultured on these scaffolds, myoblast C2C12 cells demonstrated oriented growth, highlighting the potential of aligned SF fibers in advancing skeletal muscle engineering for biomedical applications.