Aligned Nanofibers Research Articles

Regulation of Osteogenic Differentiation of hBMSCs by the Overlay Angles of Bone Lamellae-like Matrices.

Oriented fibers in bone lamellae are recognized for their contribution to the anisotropic mechanical performance of the cortical bone. While increasing evidence highlights that such oriented fibers also exhibit osteogenic induction to preosteoblasts, little is known about the effect of the overlay angle between lamellae on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). In this study, bone lamellae-like fibrous matrices composed of aligned core-shell [core: polycaprolactone (PCL)/type I collagen (Col I) + shell: Col I] nanofibers were seeded with human BMSCs (hBMSCs) and then laid over on each other layer-by-layer (L-b-L) at selected angles (0 or 45°) to form three-dimensional (3D) constructs. Upon culture for 7 and 14 days, osteogenic differentiation of hBMSCs and mineralization within the lamellae assembly (LA) were characterized by real-time PCR, Western blot, immunofluorescent staining for osteogenic markers, and alizarin red staining for calcium deposition. Compared to those of random nanofibers (LA-RF) or aligned fibers with the overlay angle of 45° (LA-AF-45), the LA of aligned fibers at a 0° overlay angle (LA-AF-0) exhibited a noticeably higher osteogenic differentiation of hBMSCs, i.e., elevated gene expression of OPN, OCN, and RUNX2 and protein levels of ALP and RUNX2, while promoting mineral deposition as indicated by alizarin red staining and mechanical testing. Further analyses of hBMSCs within LA-AF-0 revealed an increase in both total and phosphorylated integrin β1, which subsequently increased total focal adhesion kinase (FAK), phosphorylated FAK (p-FAK), and phosphorylated extracellular signal kinase ERK1/2 (p-ERK1/2). Inhibition of integrin β1 and ERK1/2 activity effectively reduced the LA-AF-0-induced upregulation of p-FAK and osteogenic markers (OPN, OCN, and RUNX2), confirming the involvement of integrin β1-FAK-ERK1/2 signaling. Altogether, the overlay angle of aligned core-shell nanofiber membranes regulates the osteogenic differentiation of hBMSCs via integrin β1-FAK-ERK1/2 signaling, unveiling the effects of anisotropic fibers on bone tissue formation.

Evaluating the efficacy of uniformly designed square mesh resin 3D printed scaffolds in directing the orientation of electrospun PCL nanofibers

Replicating the architecture of extracellular matrices (ECM) is crucial in tissue engineering to support tissues’ natural structure and functionality. The ECM’s structure plays a significant role in directing cell alignment. Electrospinning is an effective technique for fabricating nanofibrous substrates that mimic the architecture of extracellular matrices (ECM). This study aims to evaluate the efficacy of resin 3D-printed scaffolds made from a low-conductivity material (i.e., a resin composed of methacrylated oligomers, monomers, and photoinitiators) in directing the alignment of electrospun polycaprolactone (PCL) nanofibers. Six 3D-printed scaffolds were fabricated using stereolithography (SLA) technology and strategically positioned on an aluminum foil collector plate during electrospinning. The structured geometry of the scaffolds, rather than the local electric field distribution, is hypothesized to guide nanofiber alignment. Images acquired through the scanning electron microscopy (SEM) were used to analyze and statistically quantify the nanofibrous scaffolds to evaluate the alignment of nanofibers over the scaffolds compared to a set of randomly deposited control nanofiber samples in the absence of the 3D printed scaffolds. SEM images also showed significant alignment of nanofibers within the pores of scaffolds, using histograms as a means for indicating the distribution of orientation angles. Statistical analysis revealed that this distribution deviates from normality due to the deviations in the tails and the existence of relatively smaller peaks at angles relative to 0°, particularly within a range of ± 50° and ± 40°. It is further found that the average peak orientation angle relative to 0° had a maximum probability of 0.014. Furthermore, the statistical analysis confirmed the distribution and significant differences in orientation between test samples with 3D-printed scaffolds and control samples. These findings demonstrate the effectiveness of resin 3D-printed scaffolds, particularly their geometric filtering effect, leading to controlled nanofiber alignment, which is proposed to be beneficial for enhancing cell adhesion, proliferation, and cell migration in tissue engineering applications.

Fabrication of 3D microfibrous composite polycaprolactone/hydroxyapatite scaffolds loaded with piezoelectric poly (lactic acid) nanofibers by sequential near-field and conventional electrospinning for bone tissue engineering

Near-field electrospinning (NFES) has recently gained considerable interest in fabricating tissue engineering scaffolds. This technique combines the advantages of both 3D printing and electrospinning. It allows for the production of fibers with smaller resolution and the ability to make regular structures with suitable pores. In this study, a microfibrous composite scaffold of polycaprolactone (PCL)/hydroxyapatite (HA) was prepared by NFES in the first step. The microfibrous scaffold had a fiber spacing of 414.674 ± 24.9 μm with an average fiber diameter of 94.695 ± 16.149 μm. However, due to the large fiber spacing, the surface area was insufficient for cell adhesion. Therefore, the hybrid scaffold was prepared by adding aligned and random electrospun poly (L-lactic acid) (PLLA) nanofibers to the microfibrous scaffold. Cellular studies showed that cell adhesion to the hybrid scaffold increased by 334 % compared to the microfibrous scaffold. These nanofibers also exhibited piezoelectric properties, which helped stimulate bone regeneration. Aligned nanofibers in the hybrid scaffold enhanced alkaline phosphatase activity and the intensity of alizarin red staining 1.5 and 1.6 times, respectively, compared to the microfibrous scaffold. Furthermore, the elastic modulus and ultimate tensile strength increased by 268 % and 130 %, respectively, by adding aligned nanofibers to the microfibrous scaffold. Therefore, the hybrid microfibrous composite scaffold of PCL/HA containing aligned electrospun PLLA nanofibers with improved properties showed the potential for bone regeneration.

Latent stem cell-stimulating radially aligned electrospun nanofibrous patches for chronic tympanic membrane perforation therapy

Chronic tympanic membrane (TM) perforation is a tubotympanic disease caused by either traumatic injury or inflammation. A recent study demonstrated significant progress in promoting the regeneration of chronic TM perforations through the application of nanofibers with radially aligned nanostructures and controlled release of growth factors. However, radially aligned nanostructures with stem cell-stimulating factors have never been used. In this study, insulin-like growth factor binding factor 2 (IGFBP2)-incorporated radially aligned nanofibrous patches (IRA-NFPs) were developed and applied to regenerate chronic TM perforations. The IRA-NFPs were prepared by electrospinning 8 wt% polycaprolactone in trifluoroethanol and acetic acid (9:1). Random nanofibers (RFs) and aligned nanofibers (AFs) were successfully fabricated using a flat plate and a custom-designed circular collector, respectively. The presence of IGFBP2 was confirmed via Fourier transform infrared spectroscopy and the release of IGFBP2 was sustained for up to 20 days. In vitro studies revealed enhanced cellular proliferation and migration on AFs compared to RFs, and the incorporation of IGFBP2 further promoted these effects. Quantitative real-time PCR revealed mRNA downregulation, correlating with accelerated migration and increased cell confluency. In vivo studies showed IGFBP2-loaded RF and AF patches increased regeneration success rates by 1.59-fold and 2.23-fold, respectively, while also reducing healing time by 2.5-fold compared to the control. Furthermore, IGFBP2-incorporated AFs demonstrated superior efficacy in healing larger perforations with enhanced histological similarity to native TMs. This study, combining stem cell stimulating factors and aligned nanostructures, proposes a novel approach potentially replacing conventional surgical methods for chronic TM perforation regeneration. Statement of significanceChronic otitis media (COM) affects approximately 200 million people worldwide due to inflammation, inadequate blood supply, and lack of growth factors. Current surgical treatments have limitations like high costs and anesthetic risks. Recent research explored the use of nanofibers with radially aligned nanostructures and controlled release of growth factors to treat chronic tympanic membrane (TM) perforations. In this study, insulin-like growth factor binding protein 2 (IGFBP2)-incorporated radially aligned nanofibrous patches (IRA-NFPs) were developed and applied to regenerate chronic TM perforations. We assessed their properties and efficacy through in vitro and in vivo studies. IRA-NFPs showed promising healing capabilities with chronic TM perforation models. This innovative approach has the potential to improve COM management, reduce surgery costs, and enhance patient safety.

Magnetic-assisted alignment of nanofibers in a polymer nanocomposite for high-temperature capacitive energy storage applications.

Flexible polymer-based dielectrics with high energy storage characteristics over a wide temperature range are crucial for advanced electrical and electronic systems. However, the intrinsic low dielectric constant and drastically degraded breakdown strength hinder the development of polymer-based dielectrics at elevated temperatures. Here, we propose a magnetic-assisted approach for fabricating a polyethyleneimine (PEI)-based nanocomposite with precisely aligned nanofibers within the polymer matrix, and with Al2O3 deposition layers applied on the surface. The resulting polymer nanocomposite exhibits simultaneously increased dielectric constant and enhanced breakdown strength at high temperatures compared to pristine PEI. The enhanced dielectric constant is contributed by the depolarization effect of out-of-plane orientated nanofibers in composite films, while the surficial Al2O3 layers, with a wide bandgap, effectively prevent charge injection and transport at the electrode/dielectric interface. The optimally aligned composite films exhibit a significantly enhanced discharged energy density of 6.5 J cm-3 at 150 °C, with approximately 41% and 132% enhancement compared to random films and pristine PEI films, respectively. Additionally, a metalized multilayer polymer-based capacitor utilizing this composite film produces a high capacitance of 88 nF, while demonstrating excellent cyclability and flexibility at 150 °C. This work offers an effective strategy for developing polymer-based composite dielectrics with superior capacitive performance at elevated temperatures and demonstrates the potential of fabricating high-quality flexible capacitors.

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M‐Type Interface Integrated into Precise Co‐Culture System as Muscle‐Tendon Junction‐on‐a‐Chip for Drug Development (Small Methods 9/2024)

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M‐Type Interface Integrated into Precise Co‐Culture System as Muscle‐Tendon Junction‐on‐a‐Chip for Drug Development (Small Methods 9/2024)

A mechanically robust and optically transparent nanofiber-aerogel-reinforcing polymeric nanocomposite for passive cooling window

The development of mechanically robust, visibly transparent and infrared spectrally selective films is pivotal for enhancing the thermal insulation efficiency of transparent building envelopes such as skylights and windows. Herein, an aligned nanofiber-aerogel-reinforcing all-polymeric nanocomposite is prepared by impregnating and curing methacrylate monomers within an aligned cellulose nanofiber aerogel. The deliberately structured cellulose aerogel with an aligned porous structure perpendicular to the film plane facilitates the formation of a robust nanofiber-matrix interface within the nanocomposite. This design enhances the mechanical strength and impact resistance reaching values of 274.5 MPa and 51.1 kJ m−2, respectively. Utilized as spectrally selective transparent window materials, these nanocomposites demonstrate exceptional infrared spectral selectivity, with a visible light transmittance of up to 78.2 %, near-infrared transmittance as low as 32.3 %, and mid-infrared emissivity as high as 91.0 %. They can be directly utilized as high-strength and impact-resistant spectrally selective cooling windows for effective indoor solar energy management, offering both indoor illumination and spontaneous cooling, leading to a reduction in indoor temperatures by 3.2 °C compared to conventional glass window materials.

Surface-Conjugated Galactose on Electrospun Polycaprolactone Nanofibers: An Innovative Scaffold for Uterine Tissue Engineering.

The uterus, a vital organ in the female reproductive system, nurtures and supports developing embryos until maturity. This study focuses on addressing uterine related problems by creating a nanofibrous scaffold to regenerate uterine myometrial tissue, closely resembling the native extracellular matrix (ECM) for enhanced efficacy. To achieve this, we utilized polycaprolactone (PCL) as a biomaterial and employed an electrospinning technique to generate PCL nanofibers in both random and aligned orientations. Due to the inherent hydrophobic nature of PCL nanofibers, a two-step wet chemistry surface modification technique is used, involving the conjugation of galactose onto them. Galactose, a lectin-binding sugar, was chosen to enhance the scaffold's hydrophilicity, thereby improving cell adhesion and fostering l-selectin-based interactions between the scaffold and uterine cells. These interactions, in turn, activated uterine fibroblasts, leading to ECM remodeling. The optimized electrospinning process successfully generated random and aligned nanofibers. Subsequent surface modification was carried out, and the modified scaffold was subjected to various physicochemical characterization, such as the ninhydrin assay, enzyme-linked lectin assay techniques that revealed successful galactose conjugation, and mechanical characterization to assess any changes in material bulk properties resulting from the modification. The tensile strength of random galactose-modified PCL fibers reached 0.041 ± 0.01 MPa, outperforming random unmodified PCL fibers (0.026 ± 0.01 MPa), aligned unmodified PCL fibers (0.011 ± 0.001 MPa), and aligned modified PCL fibers (0.016 ± 0.002 MPa). Cytocompatibility studies with human uterine fibroblast cells showed enhanced viability and proliferation on the modified scaffolds. Initial pilot studies were attempted in the current study involving subcutaneous implantation in the dorsal area of Wistar rats to assess biocompatibility and tissue response before proceeding to intrauterine implantation indicated that the modification did not induce adverse inflammation in vivo. In conclusion, our study introduces a surface-modified PCL nanofibrous material for myometrial tissue engineering, offering promise in addressing myometrial damage and advancing uterine health and reproductive well-being.

The Effect of Aligned and Random Electrospun Fibers Derived from Porcine Decellularized ECM on Mesenchymal Stem Cell-Based Treatments for Spinal Cord Injury.

The impact of traumatic spinal cord injury (SCI) can be extremely devastating, as it often results in the disruption of neural tissues, impeding the regenerative capacity of the central nervous system. However, recent research has demonstrated that mesenchymal stem cells (MSCs) possess the capacity for multi-differentiation and have a proven track record of safety in clinical applications, thus rendering them effective in facilitating the repair of spinal cord injuries. It is urgent to develop an aligned scaffold that can effectively load MSCs for promoting cell aligned proliferation and differentiation. In this study, we prepared an aligned nanofiber scaffold using the porcine decellularized spinal cord matrix (DSC) to induce MSCs differentiation for spinal cord injury. The decellularization method removed 87% of the immune components while retaining crucial proteins in DSC. The electrospinning technique was employed to fabricate an aligned nanofiber scaffold possessing biocompatibility and a diameter of 720 nm. In in vitro and in vivo experiments, the aligned nanofiber scaffold induces the aligned growth of MSCs and promotes their differentiation into neurons, leading to tissue regeneration and nerve repair after spinal cord injury. The approach exhibits promising potential for the future development of nerve regeneration scaffolds for spinal cord injury treatment.

Cure-on-demand 3D printing of complex geometries for enhanced tactile sensing in soft robotics and extended reality

Replicating the tactile sensing mechanisms, conformity, and feel of real skin is essential for next-generation human–machine interfaces. However, producing tissue-like multilayered geometries and integrating them as e-skin systems requires simplifying and standardizing their manufacture. Here, we present a scalable and cost-effective cure-on-demand strategy for 3D printing nanocomposite silicone rubbers and integrating them into complex soft structures with 1200 % enhanced pressure-strain sensitivity. By utilizing a controlled in-situ mixing of catalyst-cured silicones and shear-driven alignment of carbon nanofibers (CNF), we construct percolated networks with conductivities up to 130 S m−1 layer-by-layer. We investigate the influence of ink composition, printing parameters, geometrical design, and material density on the mechanical properties, stretchability, sensitivity, and antimicrobial activity of 3D printed piezoresistive sensors and build skin-like interfaces that detect minimal deformations like human physiological signs. This customizable, biocompatible, and robust e-skin holds promise for cost-effective integration in rehabilitation medicine, smart robotics applications, and extended reality (XR) interactive experiences.

Conjugate electrospinning of aligned polymer nanofibers at different intersection angles between the oppositely charged spinning nozzles

Conjugate electrospinning of aligned polymer nanofibers at different intersection angles between the oppositely charged spinning nozzles

In situ biomineralization reinforcing anisotropic nanocellulose scaffolds for guiding the differentiation of bone marrow-derived mesenchymal stem cells

Nanocellulose (NC) is a promising biopolymer for various biomedical applications owing to its biocompatibility and low toxicity. However, it faces challenges in tissue engineering (TE) applications due to the inconsistency of the microenvironment within the NC-based scaffolds with target tissues, including anisotropy microstructure and biomechanics. To address this challenge, a facile swelling-induced nanofiber alignment and a novel in situ biomineralization reinforcement strategies were developed for the preparation of NC-based scaffolds with tunable anisotropic structure and mechanical strength for guiding the differentiation of bone marrow-derived mesenchymal stem cells for potential TE application. The bacterial cellulose (BC) and cellulose nanofibrils (CNFs) based scaffolds with tunable swelling anisotropic index in the range of 10–100 could be prepared by controlling the swelling medium. The in situ biomineralization efficiently reinforced the scaffolds with 2–4 times and 10–20 times modulus increasement for BC and CNFs, respectively. The scaffolds with higher mechanical strength were superior in supporting cell growth and proliferation, suggesting the potential application in TE application. This work demonstrated the feasibility of the proposed strategy in the preparation of scaffolds with mechanical anisotropy to induce cells-directed differentiation for TE applications.

Modified five times simulated body fluid for efficient biomimetic mineralization

Simulated body fluid (SBF) is widely utilized in preclinical research for estimating the mineralization efficacy of biomaterials. Therefore, it is of great significance to construct an efficient and stable SBF mineralization system. The conventional SBF solutions cannot maintain a stable pH value and are prone to precipitate homogeneous calcium salts at the early stages of the biomimetic process because of the release of gaseous CO2. In this study, a simple but efficient five times SBF buffered by 5 % CO2 was developed and demonstrated to achieve excellent mineralized microstructure on a type of polymer-aligned nanofibrous scaffolds, which is strikingly similar to the natural human bone tissue. Scanning electron microscopy and energy-dispersive X-ray examinations indicated the growth of heterogeneous apatite with a high-calcium-to-phosphate ratio on the aligned nanofibers under 5 times SBF buffered by 5 % CO2. Moreover, X-ray diffraction spectroscopy and Fourier transform infrared analyses yielded peaks associated with carbonated hydroxyapatite with less prominent crystallization. In addition, the biomineralized aligned polycaprolactone nanofibers demonstrated excellent cell attachment, alignment, and proliferation characteristics in vitro. Overall, the results of this study showed that 5 × SBFs buffered by 5 % CO2 partial pressure are attractive alternatives for the efficient biomineralization of scaffolds in bone tissue engineering, and could be used as a model for the prediction of the bone-bonding bioactivity of biomaterials.

Ultrasound-Responsive Aligned Piezoelectric Nanofibers Derived Hydrogel Conduits for Peripheral Nerve Regeneration.

Nerve guidance conduits (NGCs) are considered as promising treatment strategy and frontier trend for peripheral nerve regeneration, while their therapeutic outcomes are limited by the lack of controllable drug delivery and available physicochemical cues. Herein, novel aligned piezoelectric nanofibers derived hydrogel NGCs with ultrasound (US)-triggered electrical stimulation (ES) and controllable drug release for repairing peripheral nerve injury are proposed. The inner layer of the NGCs is the barium titanate piezoelectric nanoparticles (BTNPs)-doped polyvinylidene fluoride-trifluoroethylene [BTNPs/P(VDF-TrFE)] electrospinning nanofibers with improved piezoelectricity and aligned orientation. The outer side of the NGCs is the thermoresponsive poly(N-isopropylacrylamide) hybrid hydrogel with bioactive drug encapsulation. Such NGCs can not only induce neuronal-oriented extension and promote neurite outgrowth with US-triggered wireless ES, but also realize the controllable nerve growth factor release with the hydrogel shrinkage under US-triggered heating. Thus, the NGC can positively accelerate the functional recovery and nerve axonal regeneration of rat models with long sciatic nerve defects. It is believed that the proposed US-responsive aligned piezoelectric nanofibers derived hydrogel NGCs will find important applications in clinic neural tissue engineering.

Flaw sensitivity of bacterial cellulose hydrogel under monotonic and cyclic loadings

The presence of flaw in solid materials can lead to stress concentration, resulting in the reduction of rupture stress and stretchability of material. When the flaw is sufficiently smaller than a material-specific length, referred to as flaw sensitivity length, the material exhibits flaw insensitivity. The flaw sensitivity length is a critical material property that reflects how the material is sensitive or insensitive to crack. However, the impact of crack length on the load-bearing process of material remains an open problem. In this work, we characterize the flaw sensitivity of a stretchable material, bacterial cellulose hydrogel, under monotonic and cyclic loadings. Through fracture and fatigue tests, we first determine that the hydrogel exhibits high fracture toughness and fatigue resistance. We next characterize the flaw sensitivity of the hydrogel through two visualized experimental methods. Photoelasticity observation on the stress distribution in samples during loading shows that the samples with cracks below 2 mm exhibit uniform stress distribution during the deformation process, while those with cracks above 2 mm experience stress concentration at crack tip. Scanning electron microscope observation on the microstructure morphology of samples under fixed stretch shows that the samples with cracks below 2 mm exhibit uniform alignment of nanofibers, while those with cracks above 2 mm exhibit more intense alignment and even bundling of nanofibers at crack tip. Similar trends are observed in the samples under cyclic loading, where the transition length is also about 2 mm. Notably, the flaw sensitivity lengths obtained by the visualized methods agree well with that obtained by direct measurement of rupture stress and theoretical estimations under monotonic and cyclic loadings. The methods offer novel way to study the flaw sensitivity of materials, thereby contributing to the exploration of failure mechanisms.

Tunable Macroscopic Alignment of Self-Assembling Peptide Nanofibers.

Progress in the design and synthesis of nanostructured self-assembling systems has facilitated the realization of numerous nanoscale geometries, including fibers, ribbons, and sheets. A key challenge has been achieving control across multiple length scales and creating macroscopic structures with nanoscale organization. Here, we present a facile extrusion-based fabrication method to produce anisotropic, nanofibrous hydrogels using self-assembling peptides. The application of shear force coinciding with ion-triggered gelation is used to kinetically trap supramolecular nanofibers into aligned, hierarchical macrostructures. Further, we demonstrate the ability to tune the nanostructure of macroscopic hydrogels through modulating phosphate buffer concentration during peptide self-assembly. In addition, increases in the nanostructural anisotropy of fabricated hydrogels are found to enhance their strength and stiffness under hydrated conditions. To demonstrate their utility as an extracellular matrix-mimetic biomaterial, aligned nanofibrous hydrogels are used to guide directional spreading of multiple cell types, but strikingly, increased matrix alignment is not always correlated with increased cellular alignment. Nanoscale observations reveal differences in cell-matrix interactions between variably aligned scaffolds and implicate the need for mechanical coupling for cells to understand nanofibrous alignment cues. In total, innovations in the supramolecular engineering of self-assembling peptides allow us to decouple nanostructure from macrostructure and generate a gradient of anisotropic nanofibrous hydrogels. We anticipate that control of architecture at multiple length scales will be critical for a variety of applications, including the bottom-up tissue engineering explored here.

Bi-material nanofibrous electrospun junctions: A versatile tool to mimic the muscle–tendon interface

Soft robotics aims to replicate the structure and mechanics of skeletal muscles. The challenge lies in seamlessly integrating these muscle-inspired soft actuators with the joints they intend to actuate, resembling the natural connection between muscles and tendons (i.e., myotendinous junction). This study addresses this issue by producing electrospun bundles of aligned nanofibers using a thermoplastic polyurethane, mimicking the muscle fascicle, and nylon 6.6 for the tendon one. A novel method was developed to create electrospun bi-material bundles with two different types of myotendinous-inspired junctions, called flat and conical. Scanning electron microscopy and microtomography analyses confirmed that conical junctions mimicked natural myotendinous structures better than flat ones. Tensile mechanical tests demonstrated that bi-material junctions reached stress at failure comparable to polyurethane bundles (11 ± 2 MPa), with the conical junction showing stiffness (0.13 ± 0.02 N/mm) and net elastic modulus (153 ± 10 MPa) values closer to the natural myotendinous ones. Cyclic tests verified the mechanical stability of junctions and their ability to dampen nylon 6.6 hardening over time. Moreover, all bundles withstood cyclic loading without breaking. These findings suggest the potential of biomimetic electrospun junctions for applications in soft robotics, marking a significant step toward advancing this field.

Production of continuous nanofiber bundles by multi parallel electrodes in needleless electrospinning

This study explores the collection of nanofiber bundles on a conveyor belt for continuous production, contrasting with previous studies that focused on the production of limited-length nanofibers directly on electrodes. The research focuses on examining how the plate width and the gap distance within a conveyor system influence the alignment and morphology of the nanofibers. To fully understand these effects, the designs of multi parallel electrodes were analyzed using COMSOL Multiphysics. This analysis focused on determining the electric field strength, the electrical potential, and the vectors of the electric field within these systems. Additionally, the study delved into the alignment and morphology of the polyacrylonitrile nanofibers, employing a field emission scanning electron microscope for detailed observation. The findings revealed that both the width of the plates and the gap distance critically impacted the alignment and nanofiber morphology. The optimal alignment and uniformity of nanofibers were achieved at specific plate widths and gap distances, demonstrating the intricate relationship between these parameters and nanofiber characteristics.

Ti3C2Tx MXene@metal-organic frameworks-derived bead-like carbon nanofibers heterostructure aerogel for enhanced performance lithium/sodium storage

MXene has shown remarkable performance in constructing stable interfacial interactions with high metal-like conductivity and abundant surface functional groups for Li+/Na+ storage. However, traditional MXene nanosheets face challenges in commercial applications for lithium/sodium-ion batteries (LIBs/SIBs) due to aggregation and self-stacking problems. In this study, we introduced a novel porous Ti3C2Tx MXene-based heterostructure aerogel with a unique metal-organic frameworks (MOF)-derived bead-like structure. This structure is composed of MIL-88 A along the radial alignment of N-doping carbon nanofibers and layer Ti3C2Tx MXene nanosheets through a process involving electrospinning, in-situ growth, calcination and freeze-drying methods. The resulting MOF-derived bead-like structure of the heterostructure aerogel composite enables fast ion/electron diffusion and provides structural durability, thereby alleviating the accumulation of MXene nanosheets. This innovative design addresses volume expansion concerns and offers additional channels for Li+/Na+ transport. As a consequence, the obtained MOF-Fe2O3@carbon@Ti3C2Tx MXene composite nanofibers show high-rate performance, achieving 202 mAh g−1 at 10 A g−1 for LIBs and 98 mAh g−1 at 5 A g−1 for SIBs. The excellent cycling performance is observed with a capacity of 401 mAh g−1 at 2 A g−1 after 2000 cycles for LIBs and 197 mAh g−1 at 1 A g−1 after 1000 cycles for SIBs.

Composite material based on piezoelectric core-shell nanofibers for tactile recognition

In recent years, self-sensing composite materials based on the direct piezoelectric effect have attracted widespread interest as they combine the composite material's mechanical performances with the piezoelectric phase's sensing capability. In this context, piezoelectric nanofibers exhibit minimal impact on the mechanical structure of the composite – differently from bulky films or ceramic disks - and represent a promising strategy for robotic applications or wearable devices. This work aims to develop a self-sensing laminate based on piezoelectric core-shell nanofibers (PEDOT:PSS-based core and P(VDF-TrFE)-based shell). Each layer of the laminate is made of a flexible epoxy material and embeds aligned nanofibers. By orthogonally overlapping two layers, the intersection points of the matrix-like arrangement of the nanofibers generate a network of piezoelectric pixels, which are responsible for sensing. Such a self-sensing composite material exhibited a noticeable capability to recognize the exact position of a mechanical stimulus on its surface.