Application of textile technology in tissue engineering: A review

Advancements in textile techniques for cardiovascular tissue replacement and repair

In cardiovascular therapeutics, procedures such as heart transplants and coronary artery bypass graft are pivotal. However, an acute shortage of organ donors increases waiting times of patients, which is reflected in negative effects on the outcome for the patient. Post-procedural complications such as thrombotic events and atherosclerotic developments may also have grave clinical implications. To address these challenges, tissue engineering is emerging as a solution, using textile technologies to synthesize biomimetic scaffolds resembling natural tissues. This comprehensive analysis explains methodologies including electrospinning, electrostatic flocking, and advanced textile techniques developed from weaving, knitting, and braiding. These techniques are evaluated in the context of fabricating cardiac patches, vascular graft constructs, stent designs, and state-of-the-art wearable sensors. We also closely examine the interaction of distinct process parameters with the biomechanical and morphological attributes of the resultant scaffolds. The research concludes by combining current findings and recommendations for subsequent investigation.

Automated model discovery for textile structures: The unique mechanical signature of warp knitted fabrics

Textile fabrics have unique mechanical properties, which make them ideal candidates for many engineering and medical applications: They are initially flexible, nonlinearly stiffening, and ultra-anisotropic. Various studies have characterized the response of textile structures to mechanical loading; yet, our understanding of their exceptional properties and functions remains incomplete. Here we integrate biaxial testing and constitutive neural networks to automatically discover the best model and parameters to characterize warp knitted polypropylene fabrics. We use experiments from different mounting orientations, and discover interpretable anisotropic models that perform well during both training and testing. Our study shows that constitutive models for warp knitted fabrics are highly sensitive to an accurate representation of the textile microstructure, and that models with three microstructural directions outperform classical orthotropic models with only two in-plane directions. Strikingly, out of 214=16,384 possible combinations of terms, we consistently discover models with two exponential linear fourth invariant terms that inherently capture the initial flexibility of the virgin mesh and the pronounced nonlinear stiffening as the loops of the mesh tighten. We anticipate that the tools we have developed and prototyped here will generalize naturally to other textile fabrics-woven or knitted, weft knit or warp knit, polymeric or metallic-and, ultimately, will enable the robust discovery of anisotropic constitutive models for a wide variety of textile structures. Beyond discovering constitutive models, we envision to exploit automated model discovery as a novel strategy for the generative material design of wearable devices, stretchable electronics, and smart fabrics, as programmable textile metamaterials with tunable properties and functions. Our source code, data, and examples are available at https://github.com/LivingMatterLab/CANN. STATEMENT OF SIGNIFICANCE: Textile structures are rapidly gaining popularity in many biomedical applications including tissue engineering, wound healing, and surgical repair. A precise understanding of their unique mechanical properties is critical to tailor them to their specific functions. Here we integrate mechanical testing and machine learning to automatically discover the best models for knitted polypropylene fabrics. We show that warp knitted fabrics possess a complex symmetry with three distinct microstructural directions. Along these, the behavior is dominated by an exponential linear term that characterize the initial flexibility of the virgin mesh and the nonlinear stiffening as the loops of the fabric tighten. We expect that our technology will generalize naturally to other fabrics and enable the robust discovery of complex anisotropic models for a wide variety of textile structures.

O-carboxymethyl chitosan in biomedicine: A review

O-carboxymethyl chitosan (O-CMC) is a chitosan derivative produced through the substitution of hydroxyl (-OH) functional groups in glucosamine units with carboxymethyl (-CH2COOH) substituents, effectively addressing the inherent solubility issues of chitosan in aqueous solutions. O-CMC has garnered significant interest due to its enhanced solubility, elevated viscosity, minimal toxicity, and advantageous biocompatibility properties. Furthermore, O-CMC demonstrates antibacterial, antifungal, and antioxidant characteristics, rendering it a promising candidate for various biomedical uses such as wound healing, tissue engineering, anti-tumor therapies, biosensors, and bioimaging. Additionally, O-CMC is well-suited for the fabrication of nanoparticles, hydrogels, films, microcapsules, and tablets, offering opportunities for effective drug delivery systems. This review outlines the distinctive features of O-CMC, offers analyses of advancements and future potential based on current research, examines significant obstacles for clinical implementation, and foresees its ongoing significant impacts in the realm of biomedicine.

Nanofiber Graft Therapy to Prevent Shoulder Stiffness and Adhesions after Rotator Cuff Tendon Repair: A Comprehensive Review

Stiffness and adhesions following rotator cuff tears (RCTs) are common complications that negatively affect surgical outcomes and impede healing, thereby increasing the risk of morbidity and failure of surgical interventions. Tissue engineering, particularly through the use of nanofiber scaffolds, has emerged as a promising regenerative medicine strategy to address these complications. This review critically assesses the efficacy and limitations of nanofiber-based methods in promoting rotator cuff (RC) regeneration and managing postrepair stiffness and adhesions. It also discusses the need for a multidisciplinary approach to advance this field and highlights important considerations for future clinical trials.

Production and Characterization of Melt-Spun Poly(3-hydroxybutyrate)/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Blend Monofilaments

We investigated the melt-spinning potential of a poly(3-hydroxybutyrate)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blend using a piston spinning machine with two different spinneret diameters (0.2 and 0.5 mm). Results from the differential scanning calorimetry, dynamic mechanical thermal analysis, and tensile testing showed distinct filament properties depending on the monofilaments' cross-sectional area. Finer filaments possessed different melting behaviors compared to the coarser filaments and the neat polymer, indicating the formation of a different type of polymer crystal. Additionally, the mechanical properties of the finer filament (tensile strength: 21.5 MPa and elongation at break: 341%) differed markedly from the coarser filament (tensile strength: 11.7 MPa, elongation at break: 12.3%). The hydrolytic stability of the filaments was evaluated for 7 weeks in a phosphate-buffered saline solution and showed a considerably reduced elongation at break of the thinner filaments. Overall, the results indicate considerable potential for further filament improvements to facilitate textile processing.

Enhancing tendon-bone integration and healing with advanced multi-layer nanofiber-reinforced 3D scaffolds for acellular tendon complexes

Advancements in tissue engineering are crucial for successfully healing tendon-bone connections, especially in situations like anterior cruciate ligament (ACL) restoration. This study presents a new and innovative three-dimensional scaffold, reinforced with nanofibers, that is specifically intended for acellular tendon complexes. The scaffold consists of a distinct layered arrangement comprising an acellular tendon core, a middle layer of polyurethane/type I collagen (PU/Col I) yarn, and an outside layer of poly (L-lactic acid)/bioactive glass (PLLA/BG) nanofiber membrane. Every layer is designed to fulfill specific yet harmonious purposes. The acellular tendon core is a solid structural base and a favorable environment for tendon cell functions, resulting in considerable tensile strength. The central PU/Col I yarn layer is vital in promoting the tendinogenic differentiation of stem cells derived from tendons and increasing the expression of critical tendinogenic factors. The external PLLA/BG nanofiber membrane fosters the process of bone marrow mesenchymal stem cells differentiating into bone cells and enhances the expression of markers associated with bone formation. Our scaffold's biocompatibility and multi-functional design were confirmed through extensive in vivo evaluations, such as histological staining and biomechanical analyses. These assessments combined showed notable enhancements in ACL repair and healing. This study emphasizes the promise of multi-layered nanofiber scaffolds in orthopedic tissue engineering and also introduces new possibilities for the creation of improved materials for regenerating the tendon-bone interface.

3D Printing of Polysaccharide-Based Hydrogel Scaffolds for Tissue Engineering Applications: A Review

In tissue engineering, 3D printing represents a versatile technology employing inks to construct three-dimensional living structures, mimicking natural biological systems. This technology efficiently translates digital blueprints into highly reproducible 3D objects. Recent advances have expanded 3D printing applications, allowing for the fabrication of diverse anatomical components, including engineered functional tissues and organs. The development of printable inks, which incorporate macromolecules, enzymes, cells, and growth factors, is advancing with the aim of restoring damaged tissues and organs. Polysaccharides, recognized for their intrinsic resemblance to components of the extracellular matrix have garnered significant attention in the field of tissue engineering. This review explores diverse 3D printing techniques, outlining distinctive features that should characterize scaffolds used as ideal matrices in tissue engineering. A detailed investigation into the properties and roles of polysaccharides in tissue engineering is highlighted. The review also culminates in a profound exploration of 3D polysaccharide-based hydrogel applications, focusing on recent breakthroughs in regenerating different tissues such as skin, bone, cartilage, heart, nerve, vasculature, and skeletal muscle. It further addresses challenges and prospective directions in 3D printing hydrogels based on polysaccharides, paving the way for innovative research to fabricate functional tissues, enhancing patient care, and improving quality of life.

Drug eluting protein and polysaccharides-based biofunctionalized fabric textiles- pioneering a new frontier in tissue engineering: An extensive review

In the ever-evolving landscape of tissue engineering, medicated biotextiles have emerged as a game-changer. These remarkable textiles have garnered significant attention for their ability to craft tissue scaffolds that closely mimic the properties of natural tissues. This comprehensive review delves into the realm of medicated protein and polysaccharide-based biotextiles, exploring a diverse array of fabric materials. We unravel the intricate web of fabrication methods, ranging from weft/warp knitting to plain/stain weaving and braiding, each lending its unique touch to the world of biotextiles creation. Fibre production techniques, such as melt spinning, wet/gel spinning, and multicomponent spinning, are demystified to shed light on the magic behind these ground-breaking textiles. The biotextiles thus crafted exhibit exceptional physical and chemical properties that hold immense promise in the field of tissue engineering (TE). Our review underscores the myriad applications of drug-eluting protein and polysaccharide-based textiles, including TE, tissue repair, regeneration, and wound healing. Additionally, we delve into commercially available products that harness the potential of medicated biotextiles, paving the way for a brighter future in healthcare and regenerative medicine. Step into the world of innovation with medicated biotextiles-where science meets the art of healing.

Dual Factor-Loaded Artificial Periosteum Accelerates Bone Regeneration

In the clinic, inactivation of osteosarcoma using microwave ablation would damage the periosteum, resulting in frequent postoperative complications. Therefore, the development of an artificial periosteum is crucial for postoperative healing. In this study, we prepared an artificial periosteum using silk fibroin (SF) loaded with stromal cell-derived factor-1α (SDF-1α) and calcitonin gene-related peptide (CGRP) to accelerate bone remodeling after the microwave ablation of osteosarcoma. The prepared artificial periosteum showed a sustained release of SDF-1α and CGRP after 14 days of immersion. In vitro culture of rat periosteal stem cells (rPDSCs) demonstrated that the artificial periosteum is favorable for cell recruitment, the activity of alkaline phosphatase, and bone-related gene expression. Furthermore, the artificial periosteum improved the tube formation and angiogenesis-related gene expression of human umbilical vein endothelial cells (HUVECs). In an animal study, the periosteum in the femur of a rabbit was inactivated through microwave ablation and then removed. The damaged periosteum was replaced with the as-prepared artificial periosteum and favored bone regeneration. In all, the designed dual-factor-loaded artificial periosteum is a promising strategy to replace the damaged periosteum in the therapy of osteosarcoma for a better bone-rebuilding process.

Tailoring the pore design of embroidered structures by melt electrowriting to enhance the cell alignment in scaffold-based tendon reconstruction

Tissue engineering of ligaments and tendons aims to reproduce the complex and hierarchical tissue structure while meeting the biomechanical and biological requirements. For the first time, the additive manufacturing methods of embroidery technology and melt electrowriting (MEW) were combined to mimic these properties closely. The mechanical benefits of embroidered structures were paired with a superficial micro-scale structure to provide a guide pattern for directional cell growth. An evaluation of several previously reported MEW fiber architectures was performed. The designs with the highest cell orientation of primary dermal fibroblasts were then applied to embroidery structures and subsequently evaluated using human adipose-derived stem cells (AT-MSC). The addition of MEW fibers resulted in the formation of a mechanically robust layer on the embroidered scaffolds, leading to composite structures with mechanical properties comparable to those of the anterior cruciate ligament. Furthermore, the combination of embroidered and MEW structures supports a higher cell orientation of AT-MSC compared to embroidered structures alone. Collagen coating further promoted cell attachment. Thus, these investigations provide a sound basis for the fabrication of heterogeneous and hierarchical synthetic tendon and ligament substitutes.

A Review on the Progress in Core-Spun Yarns (CSYs) Based Textile TENGs for Real-Time Energy Generation, Capture and Sensing

This review is a critical analysis of the current state-of-the-art in core spun yarn textile triboelectric nanogenerators (CSY-T-TENGs) for self-powered smart sensing applications. The rapid expansion of wireless communication, flexible conductive materials, and wearable electronics over the last ten years is now demanding autonomous energy, which has created a new research space in the field of wearable T-TENGs. Current research is exploring T-TENGs made from CSYs as stable and reliable energy harvesters and sensing devices for modern wearable IoT platforms. CSY-TENGs are emerging as an important technology due to its simple structure, low cost, and excellent performance in converting mechanical energy into electrical energy and due to its sensing ability. This paper provides a critical review on current progress, it analyzes the unique advantages of CSYs T-TENGs over conventional T-TENGs, it describes fabrication techniques and discusses the materials used along with their properties and electrical performance characteristics, and it highlights the recent advancements in their integration with self-excitation circuits, charge storage devices and IoT-enabled smart sensing applications, such as environmental and health monitoring. In the conclusion, it discusses the challenges and future directions of CSYs T-TENGs and it provides a future road map for optimization, upscaling, and commercialization of the technology.

Development of Three-Dimensional (3D) Biodegradable Polyglycolic Acid Fiber (PGA) Preforms for Scaffold Applications: Experimental Patterning and Fiber Volume Fraction-Porosity Modeling Study

Three-dimensional (3D) biodegradable polyglycolic acid fiber (PGA) preforms were developed as temporary scaffolds for three-dimensional tissue regeneration applications. Three-dimensional biodegradable polyglycolic acid fiber (PGA) preforms including various degrees of interlaced structures called 3D plain, semi-interlaced, and orthogonal woven preforms were designed. Analytical relations and finite element model-based software (TexGen) on fiber volume fraction and porosity fraction were proposed to predict scaffolds' stiffness and strength properties considering micromechanics relations. It was revealed that yarn-to-yarn space, density, and angles of all 3D PGA fiber preforms were heterogeneous and demonstrated direction-dependent features (anisotropy). Total fiber volume fractions (V_fp) and porosity fraction (V_tpr) predicted by analytic and numerical modelling of all 3D scaffolds showed some deviations compared to the measured values. This was because yarn cross-sections in the scaffolds were changed from ideal circular yarn (fiber TOW) geometry to high-order ellipse (lenticular) due to inter-fiber pressure generated under a tensile-based macrostress environment during preform formation. Z-yarn modulus (E_z-yarn) and strength (σ_z-yarn) were probably critical values due to strong stiffness and strength in the through-the-thickness direction where hydrogel modulus and strengths were negligibly small. Morphology of the scaffold showed that PGA fiber sets in the preform were locally distorted, and they appeared as inconsistent and inhomogeneous continuous fiber forms. Additionally, various porosity shapes in the preform based on the virtual model featured complex shapes from nearly trapezoidal beams to partial or concave rectangular beams and ellipsoid rectangular cylinders. It was concluded that 3D polyglycolic acid fiber preforms could be a temporary supportive substrate for 3D tissue regeneration because cells in the scaffold's thickness can grow via through-the-thickness fiber (z-yarn), including various possible mechanobiology mechanisms.

Tough, Transparent, and Slippery PVA Hydrogel Led by Syneresis

Slippery and transparent polyvinyl alcohol (PVA) hydrogels with mechanical robustness exhibit broad applications in artificial biological soft tissues, flexible wearable electronics, and implantable biomedical devices. Most of the current PVA hydrogels, however, are unable to integrate these features, which compromises its performance in biological and engineering applications. To achieve such purpose, herein, a novel tactic is proposed, salting-out-after-syneresis of PVA, to realize a mechanically robust and highly transparent slippery PVA hydrogel. The syneresis of PVA sol is first conducted to form highly dense and transparent PVA polymer networks, then the salting-out effect tunes the aggregation of the polymer chains to rapidly induce the phase separation and crystallization. The resultant hydrogels show the transparency up to 98% in the visible region, the tribological coefficient down to 0.0081, and the excellent mechanical properties with strength, modulus, and toughness of 26.72 ± 1.05, 6.66 ± 0.29 MPa, and 55.21 ± 1.62 MJ m^-3 , respectively. To reveal the potentials, PVA contact lens that combine remarkable lubrication, anti-protein adhesion, biocompatibility, and drug-loading functions are demonstrated. This strategy provides a simple and new avenue for developing the mechanically robust, transparent, and hydrated hydrogels, showing the potential in biomedicine and wearable devices.

Designing an Innovative Electrospinning Strategy to Generate PHBV Nanofiber Scaffolds with a Radially Oriented Fibrous Pattern

Electrospinning has contributed substantially to the construction of nanofibrous scaffolds for potential tissue engineering and regenerative medicine applications. However, conventional electrospinning only has the ability to generate and collect nanofiber scaffolds with a randomly oriented fibrous pattern, which lack the necessary cell alignment guidance function. In this study, a novel electrospinning fiber-collecting device was designed and developed by setting a series of small pin-ring-structured collectors on a large plain plate. Specifically, we demonstrated that the pin-ring-structured collectors, which were constructed by inserting a metal pin into the center of a metal ring, could collect the as-electrospun nanofibers with radially oriented structures in an innovative manner. We first investigated the suitable polymeric concentration for electrospinning poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and the optimum electrospinning concentration of PHBV was found to be 12% (w/v) PHBV dissolved in hexafluoroisopropyl alcohol (HFIP). Then, 12% (w/v) PHBV solution was electrospun into radially oriented nanofiber scaffolds using our novel electrospinning strategy, and their various performances were further compared with conventionally randomly oriented nanofiber scaffolds that were also produced from 12% (w/v) PHBV solution. The results showed that the radially oriented PHBV nanofiber scaffolds exhibited obviously enhanced mechanical properties and decreased hydrophobicity compared with the randomly oriented PHBV nanofiber scaffold controls. Importantly, the biological properties of radially oriented PHBV nanofiber scaffolds were also demonstrated to be enhanced, compared with randomly oriented PHBV nanofiber scaffolds, by effectively inducing cell alignment and significantly promoting cell proliferation. In sum, the present study indicates that our as-prepared nanofiber scaffolds with a radially oriented pattern are of great interest for advanced applications, such as wound dressings and tissue-engineered scaffolds.

Comparison of NIH 3T3 Cellular Adhesion on Fibrous Scaffolds Constructed from Natural and Synthetic Polymers

Polymer scaffolds are increasingly ubiquitous in the field of tissue engineering in improving the repair and regeneration of damaged tissue. Natural polymers exhibit better cellular adhesion and proliferation than biodegradable synthetics but exhibit inferior mechanical properties, among other disadvantages. Synthetic polymers are highly tunable but lack key binding motifs that are present in natural polymers. Using collagen and poly(lactic acid) (PLA) as models for natural and synthetic polymers, respectively, an evaluation of the cellular response of embryonic mouse fibroblasts (NIH 3T3 line) to the different polymer types was conducted. The samples were analyzed using LIVE/DEAD™, alamarBlue™, and phalloidin staining to compare cell proliferation on, interaction with, and adhesion to the scaffolds. The results indicated that NIH3T3 cells prefer collagen-based scaffolds. PLA samples had adhesion at the initial seeding but failed to sustain long-term adhesion, indicating an unsuitable microenvironment. Structural differences between collagen and PLA are responsible for this difference. Incorporating cellular binding mechanisms (i.e., peptide motifs) utilized by natural polymers into biodegradable synthetics offers a promising direction for biomaterials to become biomimetic by combining the advantages of synthetic and natural polymers while minimizing their disadvantages.

3-D tissue-engineered epidermis against human primary keratinocytes apoptosis via relieving mitochondrial oxidative stress in wound healing

The tissue-engineered epidermal (TEE), composed of biocompatible vectors and autogenous functional cells, is a novel strategy to solve the problem of shortage of donor skin sources. The human primary keratinocyte (HPK), the major skin components, are self-evident vital in wound healing and was considered as one of the preferred seed cells for TEEs. Since the process of separating HPKs from the skin triggers a stress state of the cells, achieving its rapid adhesion and proliferation on biomaterials remains challenging. The key to the clinical application is to ensure the normal function of cells while improving the proliferation ability in vitro, and to complete the complex mesenchymal epithelialization to achieve tissue remodeling after vivo implantation. Herein, in order to aid HPKs adhesion and proliferation in vitro and promoting wound healing, we developed a three dimensional collagen scaffold with Y-27632 sustainedly released from the nanoplatform, hollow mesoporous organosilica nanoparticles (HMON). The results showed that the porous structure within the TEE supports the implanted HPKs expanding in a three-dimensional mode to jointly construct the tissue-engineered epidermis in vitro and inhibited the mitochondria-mediated cell apoptosis. It was confirmed that the TEEs with suitable degradation rate could maintain drug release after implantation and could accelerate vascularization of wound base and further revealed the involvement of mesenchymal transformation of transplanted HPKs during skin regeneration in a nude mouse model with full-thickness skin resection. In conclusion, our study highlights the great potential of constructing TEE using a nanoparticle platform for the treatment of large-area skin defects.

3D-Braided Poly-ε-Caprolactone-Based Scaffolds for Ligament Tissue Engineering

The anterior cruciate ligament (ACL) is the most commonly injured intra-articular ligament of the knee. Due to its limited intrinsical healing potential and vascularization, injuries of the ACL do not heal satisfactorily, and surgical intervention is usually required. The limitations of existing reconstructive grafts and autologous transplants have prompted interest in tissue-engineered solutions. A tissue engineering scaffold for ACL reconstruction must be able to mimic the mechanical properties of the native ligament, provide sufficient porosity to promote cell growth of the neoligament tissue, and be biodegradable. This study investigates long-term biodegradable poly-ε-caprolactone (PCL)-based scaffolds for ACL replacement using the 3D hexagonal braiding technique. The scaffolds were characterized mechanically as well as morphologically. All scaffolds, regardless of their braid geometry, achieved the maximum tensile load of the native ACL. The diameter of all scaffolds was lower than that of the native ligament, making the scaffolds implantable with established surgical methods. The 3D hexagonal braiding technique offers a high degree of geometrical freedom and, thus, the possibility to develop novel scaffold architectures. Based on the findings of this study, the 3D-braided PCL-based scaffolds studied were found to be a promising construct for tissue engineering of the anterior cruciate ligament.

Development of Biodegradable Polymeric Stents for the Treatment of Cardiovascular Diseases

Cardiovascular disease has become the leading cause of death. A vascular stent is an effective means for the treatment of cardiovascular diseases. In recent years, biodegradable polymeric vascular stents have been widely investigated by researchers because of its degradability and clinical application potential for cardiovascular disease treatment. Compared to non-biodegradable stents, these stents are designed to degrade after vascular healing, leaving regenerated healthy arteries. This article reviews and summarizes the recent advanced methods for fabricating biodegradable polymeric stents, including injection molding, weaving, 3D printing, and laser cutting. Besides, the functional modification of biodegradable polymeric stents is also introduced, including visualization, anti-thrombus, endothelialization, and anti-inflammation. In the end, the challenges and future perspectives of biodegradable polymeric stents were discussed.

Recent advances and trends in the applications of MXene nanomaterials for tissue engineering and regeneration

MXene, as a new two-dimensional nanomaterial, is endowed with lots of particular properties, such as large surface area, excellent conductivity, biocompatibility, biodegradability, hydrophilicity, antibacterial activity, and so on. In the past few years, MXene nanomaterials have become a rising star in biomedical fields including biological imaging, tumor diagnosis, biosensor, and tissue engineering. In this review, we sum up the recent applications of MXene nanomaterials in the field of tissue engineering and regeneration. First, we briefly introduced the synthesis and surface modification engineering of MXene. Then we focused on the application and development of MXene and MXene-based composites in skin, bone, nerve and heart tissue engineering. Uniquely, we also paid attention to some research on MXene with few achievements at present but might become a new trend in tissue engineering and regeneration in the future. Finally, this paper will also discuss several challenges faced by MXene nanomaterials in the clinical application of tissue engineering.

A Review of Woven Tracheal Stents: Materials, Structures, and Application

The repair and reconstruction of tracheal defects is a challenging clinical problem. Due to the wide choice of materials and structures, weaving technology has shown unique advantages in simulating the multilayer structure of the trachea and providing reliable performance. Currently, most woven stent-based stents focus only on the effect of materials on stent performance while ignoring the direct effect of woven process parameters on stent performance, and the advantages of weaving technology in tissue regeneration have not been fully exploited. Therefore, this review will introduce the effects of stent materials and fabric construction on the performance of tracheal stents, focusing on the effects of weaving process parameters on stent performance. We will summarize the problems faced by woven stents and possible directions of development in the hope of broadening the technical field of artificial trachea preparation.

Advanced Nanofiber-Based Scaffolds for Achilles Tendon Regenerative Engineering

The Achilles tendon (AT) is responsible for running, jumping, and standing. The AT injuries are very common in the population. In the adult population (21–60 years), the incidence of AT injuries is approximately 2.35 per 1,000 people. It negatively impacts people’s quality of life and increases the medical burden. Due to its low cellularity and vascular deficiency, AT has a poor healing ability. Therefore, AT injury healing has attracted a lot of attention from researchers. Current AT injury treatment options cannot effectively restore the mechanical structure and function of AT, which promotes the development of AT regenerative tissue engineering. Various nanofiber-based scaffolds are currently being explored due to their structural similarity to natural tendon and their ability to promote tissue regeneration. This review discusses current methods of AT regeneration, recent advances in the fabrication and enhancement of nanofiber-based scaffolds, and the development and use of multiscale nanofiber-based scaffolds for AT regeneration.

State-of-the-art review of advanced electrospun nanofiber yarn-based textiles for biomedical applications

The pandemic of the coronavirus disease 2019 (COVID-19) has made biotextiles, including face masks and protective clothing, quite familiar in our daily lives. Biotextiles are one broad category of textile products that are beyond our imagination. Currently, biotextiles have been routinely utilized in various biomedical fields, like daily protection, wound healing, tissue regeneration, drug delivery, and sensing, to improve the health and medical conditions of individuals. However, these biotextiles are commonly manufactured with fibers with diameters on the micrometer scale (> 10 μm). Recently, nanofibrous materials have aroused extensive attention in the fields of fiber science and textile engineering because the fibers with nanoscale diameters exhibited obviously superior performances, such as size and surface/interface effects as well as optical, electrical, mechanical, and biological properties, compared to microfibers. A combination of innovative electrospinning techniques and traditional textile-forming strategies opens a new window for the generation of nanofibrous biotextiles to renew and update traditional microfibrous biotextiles. In the last two decades, the conventional electrospinning device has been widely modified to generate nanofiber yarns (NYs) with the fiber diameters less than 1000 nm. The electrospun NYs can be further employed as the primary processing unit for manufacturing a new generation of nano-textiles using various textile-forming strategies. In this review, starting from the basic information of conventional electrospinning techniques, we summarize the innovative electrospinning strategies for NY fabrication and critically discuss their advantages and limitations. This review further covers the progress in the construction of electrospun NY-based nanotextiles and their recent applications in biomedical fields, mainly including surgical sutures, various scaffolds and implants for tissue engineering, smart wearable bioelectronics, and their current and potential applications in the COVID-19 pandemic. At the end, this review highlights and identifies the future needs and opportunities of electrospun NYs and NY-based nanotextiles for clinical use.

Electrospun strong, bioactive, and bioabsorbable silk fibroin/poly (L-lactic-acid) nanoyarns for constructing advanced nanotextile tissue scaffolds

Bio-textiles have aroused attractive attentions in tissue engineering and regenerative medicine, and developing robust, bio-absorbable, and extracellular matrix (ECM) fibril-mimicking nanofibrous textiles is urgently required for the renewal of existing microfibrous textile-based scaffolds and grafts. In this study, an integrated electrospinning system consisting of one nanoyarn-forming unit and one hot stretching unit is reported to fabricate silk fibroin (SF)/poly (L-lactic-acid) (PLLA) nanofibrous yarns (nanoyarns). The hot stretching process is demonstrated to significantly improve the fiber alignment, crystallinity, and mechanical properties of SF/PLLA nanoyarns, compared to the unstretched controls. For instance, the fiber alignment degree of hot stretched 50/50 SF/PLLA nanoyarn has increased by 25%, and the failure strength has increased by 246.5%, compared with the corresponding un-stretched control. Increasing the SF/PLLA mass ratio is found to significantly decrease the crystallinity and mechanical properties, but notably increase the degradation rate and surface hydrophilicity of SF/PLLA nanoyarns. Different SF/PLLA nanoyarns are further meticulously interwoven with warp and weft directions to obtain several nanofibrous woven textiles. The results from in vitro cell characterization and in vivo subcutaneous implantation show that increasing the SF/PLLA mass ratio significantly improves the biological properties and effectively reduces the inflammatory response of nanoyarn-constructed textiles. Overall, this study demonstrates that our SF/PLLA nanoyarns with controllable physical, mechanical and biological performances are fantastic candidates for the designing and development of advanced nanoarchitectured textile tissue scaffolds.