Fibrous Scaffolds Research Articles

Recent Advances of Macrostructural Porous Silicon for Biomedical Applications.

Porous silicon (pSi) has gained substantial attention as a versatile material for various biomedical applications due to its unique structural and functional properties. Initially used as a semiconductor material, pSi has transitioned into a bioactive platform, enabling its use in drug delivery systems, biosensing, tissue engineering scaffolds, and implantable devices. This review explores recent advancements in macrostructural pSi, emphasizing its biocompatibility, biodegradability, high surface area, and tunable properties. In drug delivery, pSi's potential for controlled and sustained release of therapeutic agents has been well-studied, making it suitable for chronic disease treatment. Innovative approaches, like microneedle arrays and hybrid drug delivery systems, are highlighted, along with challenges, such as scalability and stability, in biological environments. pSi-based biosensors offer exceptional sensitivity for detecting biomarkers, benefiting early disease diagnosis. In tissue engineering, fibrous and particulate pSi scaffolds mimic the extracellular matrix, promoting cell proliferation and tissue regeneration. pSi is also gaining momentum in orthopedic implants, demonstrating the potential for bone regeneration. Despite its promise, challenges like mechanical strength, scalability, and long-term stability must be addressed. Looking forward, future research should focus on optimizing production methods, enhancing stability, and exploring hybrid materials for pSi, paving the way for its widespread clinical use in personalized medicine, advanced drug delivery, and next-generation biosensors and implants.

Effects of polylactic acid scaffolds with various orientations and diameters on osteogenesis and angiogenesis.

Researchers in the field of regenerative medicine have consistently focused on the biomimetic design of engineered bone materials on the basis of the microstructure of natural bone tissue. Additionally, the effects of the micromorphological characteristics of these materials on angiogenesis have garnered increasing attention. In vitro, the orientation and diameter of scaffold materials can exert different effects on osteogenesis and vascularisation. However, more comprehensive investigations, including in vivo studies, are required to confirm the results observed in vitro. Accordingly, in the present study, fibre scaffolds with various orientations and diameters were prepared by electrospinning with polylactic acid. The effects of the micromorphological characteristics of these scaffolds with different orientations and diameters on osteogenesis and vascularisation were systematically studied via in vivo experiments. The scaffolds with aligned micromorphological features positively affected osteogenesis and vascularisation, which indicated that such characteristics could be considered crucial factors when designing materials for bone repair.

Pioneering a New Era in Oral Cancer Treatment with Electrospun Nanofibers: A Comprehensive Insight.

Oral cancer, currently ranked 16th among the most prevalent malignancies worldwide according to GLOBOCAN, presents significant challenges to global oral health. Conventional treatment modalities such as surgery, radiation, and chemotherapy often have limitations, prompting the need for innovative therapeutic approaches. Tissue engineering has emerged as a promising solution aimed at developing biocompatible, functional, and biologically responsive tissue constructs. This approach involves the integration of cells, bioactive compounds, and scaffolds to enhance treatment efficacy. Electrospun nanofibers, mimicking the extracellular matrix, exhibit considerable potential in addressing complex oral health issues by influencing cellular behavior. The versatility of electrospinning technology allows for the fabrication of fiber scaffolds with high surface area, making them ideal for localized delivery of bioactive compounds or pharmaceuticals. Enhancing these electrospun scaffolds with growth factors, nanoparticles, and biologically active substances significantly increases their therapeutic appeal in oral cancer management. This review offers a comprehensive examination of the various applications of electrospun nanofibers in oral cancer therapy. Utilizing electronic databases such as PubMed, CrossREF, and Google Scholar, we conducted an extensive review of relevant literature concerning "electrospun nanofibers" and their therapeutic potential in oral cancer treatment. Key topics addressed include engineering methodologies, drug diffusion mechanisms, factors influencing nanofiber scaffold design, toxicity concerns, and clinical implications. The findings underscore the transformative potential of electrospun nanofibers in revolutionizing oral cancer therapy.

Fusion of polymer-coated liposomes and centrifugally spun microfibers as hybrid materials to enhance sustained release.

Liposomes are employed for the delivery of molecular cargo in several classes of systems. For instance, the embedding of loaded liposomes in polymeric fibrous scaffolds has enabled the creation of hybrid materials that mimic biological membranes. Liposomes with unmodified surfaces have been predominantly integrated into fibers, which leads to instabilities due to interfacial incompatibility. In addition, electrospinning has been almost exclusively employed for fiber fabrication, which limits the potential for scale-up production. Here, we present the fabrication of hybrid biomimetic materials by fusing polymer-coated liposomes to force-spun microfibers to increase the stability of the hybrid materials and enhance the sustained release of the cargo. l-α-Phosphatidylcholine liposomes were coated with chitosan or polyethylene glycol (PEG). The nano-differential scanning calorimetry results confirm that polymer coating does not affect the phase transition temperature (T m) of the liposomes, where only the model drug, quercetin, reduced T m. Centrifugal spinning was employed to fabricate hydrophobic polycaprolactone (PCL) microfibers at various polymer concentrations and using various solvents and spinning parameters to increase the yield at the lowest fiber diameter. The highest microfiber production rate obtained occurred at a 20% (w/v) PCL concentration in 50 : 50 (v/v) chloroform and methanol solution with an average fiber diameter of 584.85 ± 26.30 nm. The non-chemical fusion of the polymer-coated liposomes and the fibrous scaffolds was promoted by immersion at T > T m, under ultrasonication. We hypothesize that the fusion is driven by hydrophobic interactions between the liposomes and the fibers, which merge the materials through the lipid bilayer. The fused hybrid material solved the burst release problem observed when adhering plain liposomes to nanofibers. Both PEG and chitosan yielded a sustained release, where the release rate with the former was faster. These results demonstrate that the fusion of polymer-coated liposomes and microfibers enables more effective blending of the loaded carriers into the polymer microfibers. Ultimately, the fused liposome/microfiber hybrids are stable matrices and enhance the sustained release of molecular cargo.

Integrating electrospun aligned fiber scaffolds with bovine serum albumin-basic fibroblast growth factor nanoparticles to promote tendon regeneration

BackgroundElectrospun nanofiber scaffolds have been widely used in tissue engineering because they can mimic extracellular matrix-like structures and offer advantages including high porosity, large specific surface area, and customizable structure. In this study, we prepared scaffolds composed of aligned and random electrospun polycaprolactone (PCL) nanofibers capable of delivering basic fibroblast growth factor (bFGF) in a sustained manner for repairing damaged tendons.ResultsAligned and random PCL fiber scaffolds containing bFGF-loaded bovine serum albumin (BSA) nanoparticles (BSA-bFGF NPs, diameter 146 ± 32 nm) were fabricated, respectively. To validate the viability of bFGF-loaded aligned PCL nanofiber scaffold (aPCL + bFGF group) in tendon tissue engineering, we assessed the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage and the in vivo regeneration of tendons using a rat Achilles tendon defect model. The encapsulated bFGF could be delivered in a sustained manner in vitro. The aPCL + bFGF scaffold promoted the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage. In the repair of a rat Achilles tendon defect model, the aPCL + bFGF group showed a better repair effect. The scaffold offers a promising substrate for the regeneration of tendon tissue.ConclusionsThe aligned and random PCL fiber scaffolds containing bFGF nanoparticles were successfully prepared, and their physical and chemical properties were characterized. The aPCL + bFGF scaffold could promote the expression of the related genes and proteins of tendon-forming, facilitating tendon differentiation. In the rat Achilles tendon defect experiments, the aPCL + bFGF exhibited excellent tendon regeneration effects.Graphical

Biomimetic "Trojan Horse" Fibers Modulate Innate Immunity Cascades for Nerve Regeneration.

Neutrophil membrane vesicles (NMVs) have been successfully applied to control the inflammatory cascade after spinal cord injury (SCI) by acting as an inflammatory factor decoy to front-load the overall inflammation regulatory window; however, the mechanisms by which NMVs regulate macrophage phenotypic shifts as well as their outcomes have rarely been reported. In this study, we demonstrated the "efferocytosis-like" effect of NMVs endocytosed by macrophages, supplementing the TCA cycle intermediate metabolite α-KG by promoting glutamine metabolism, which in turn facilitates oxidative phosphorylation and inhibits the NF-κB signaling pathway to reprogram inflammatory macrophages to the pro-regenerative phenotype. Based on these findings, a "Trojan horse" composite fiber scaffold was constructed; this comprised a carboxylated poly-l-lactic acid shell encapsulated with NMVs and a core loaded with brain-derived neurotrophic factor to spatiotemporally modulate the inflammatory microenvironment by 39.23% and sustainably promote nerve regeneration by 85.67%. In vivo experiments further confirmed the effect of NMV-coated fiber scaffolds on the regulation of early innate immune inflammation and the continuous promotion of nerve regeneration. This study not only further unravels the mechanism of neutrophil membrane-macrophage interactions but also provides a strategy for coordinating inflammatory reprogramming and nerve regeneration following SCI.

Properties of Electrospun Fibers That Influence Foreign Body Response Modulation.

Improving the utility of biomedical devices implanted in subcutaneous tissue by modulating the innate immune response common to these implants is of great interest to improve their utility. Uncontrolled, most biomedical devices produce an immune reaction known broadly as the foreign body response (FBR), which ultimately isolates the device from the native tissue. The use of electrospun fibers to create a porous surface that promotes tissue in-growth and regeneration represents a new paradigm in FBR modulation. A vast number of parameters can be adjusted in the electrospinning process to tune the type and quality of the resulting electrospun matrix, which in turn has varying outcomes with respect to the FBR. In this review, the fabrication and utility of electrospun fiber scaffolds for mitigating the FBR are described, with details of how fiber properties and surface modifications alter immune response for specific biomedical applications.

Self-Assembled DNA-Collagen Bioactive Scaffolds Promote Cellular Uptake and Neuronal Differentiation.

Different modalities of DNA/collagen complexes have been utilized primarily for gene delivery studies. However, very few studies have investigated the potential of these complexes as bioactive scaffolds. Further, no studies have characterized the DNA/collagen complex formed from the interaction of the self-assembled DNA macrostructure and collagen. Toward this investigation, we report herein the fabrication of novel bioactive scaffolds formed from the interaction of sequence-specific, self-assembled DNA macrostructure and collagen type I. Varying molar ratios of DNA and collagen resulted in highly intertwined fibrous scaffolds with different fibrillar thicknesses. The formed scaffolds were biocompatible and presented as a soft matrix for cell growth and proliferation. Cells cultured on DNA/collagen scaffolds promoted the enhanced cellular uptake of transferrin, and the potential of DNA/collagen scaffolds to induce neuronal cell differentiation was further investigated. The DNA/collagen scaffolds promoted neuronal differentiation of precursor cells with extensive neurite growth in comparison to the control groups. These novel, self-assembled DNA/collagen scaffolds could serve as a platform for the development of various bioactive scaffolds with potential applications in neuroscience, drug delivery, tissue engineering, and in vitro cell culture.

A Promising Approach to Ultra-Flexible 1 Ah Lithium-Sulfur Batteries Using Oxygen-Functionalized Single-Walled Carbon Nanotubes.

Lithium-sulfur (Li-S) batteries represent a promising solution for achieving high energy densities exceeding 500Wh kg-1, leveraging cathode materials with theoretical energy densities up to 2600Wh kg-1. These batteries are also cost-effective, abundant, and environment-friendly. In this study, an innovative approach is proposed utilizing highly oxidized single-walled carbon nanotubes (Ox-SWCNTs) as a conductive fibrous scaffold and functional interlayer in sulfur cathodes and separators, respectively, to demonstrate large-area and ultra-flexible Li-S batteries with enhanced energy density. The free-standing sulfur cathodes in the Li-S cells exhibit high energy density maintaining 806 mAh g-1 even after 100 charge-discharge cycles. Additionally, oxygen-containing functional groups on the SWCNTs significantly improve electrochemical performance by promoting the adsorption of lithium polysulfides. Employing Ox-SWCNTs in both cathodes and interlayers, the study achieves high-capacity Li-S pouch cells that consistently deliver a capacity of 1.06 Ah and a high energy density of 909 mAh g-1 over 50 charge-discharge cycles. This strategy not only significantly enhances the electrochemical performance of Li-S batteries but also maintains excellent mechanical flexibility under severe deformation, positioning this Ox-SWCNT-based architecture as a viable, light-weight, and ultra-flexible energy storage solution suitable for commercializing rechargeable Li-S batteries.

Preparation and Characterization of Crimped PLA Fibers With Surface Porous Structure to Promote Cell Adhesion and Growth

ABSTRACTElectrospun fibrous scaffolds are widely used in vascular tissue engineering because they are able to mimic the organizational structure and biological function of a natural extracellular matrix. Improving the topological structure and mechanical properties of electrospun fibrous scaffolds is crucial for achieving good interaction between cells and materials. Herein, oriented polylactic acid (PLA) fibers with surface porous structure were prepared by electrospinning. The orientation degree of the surface porous structure (84.77° ± 5.61°) was highly consistent with the orientation degree of the fiber (83.66° ± 7.31°), which improved the porosity of the fiber and promoted the adhesion of human umbilical vein endothelial cells (HUVECs). Then, by heat treatment, oriented PLA fibers with a surface porous structure were formed into a crimped state, which mimics the crimped structure and nonlinear mechanical properties of the elastic fibers within the blood vessel wall. The crimped PLA fibers with surface porous structure significantly improved the aspect ratio of HUVECs and promoted HUVECs‐oriented growth, which shows certain potential applications in vascular tissue engineering.

Quantifying Biomass and Visualizing Cell Coverage on Fibrous Scaffolds for Cultivated Meat Production.

Cultivated meat represents a transformative solution to environmental and ethical concerns of traditional meat industries, replicating livestock meat's texture and sensory attributes in vitro with a focus on cost, safety, and nutritional quality. Central to this process are biomaterial scaffolds that support tissue development from isolated animal cells grown in or on these matrices. Understanding scaffold interactions with cells, including scaffold degradation and biomass production, is crucial for process design and for scaling-up goals. In this article, we outline comprehensive methods to quantify scaffold-cell interactions for such scenarios, focusing on biomaterial scaffold degradation and changes in cell biomass [measured by cell weight, extracellular matrix (ECM) deposition, and cell coverage] during cell culture. We introduce two methodologies for assessing cell coverage: fixation and staining for detailed imaging analysis, and non-invasive, real-time evaluation across scaffolds. Here we focus on fiber-based scaffolds, while the assessments can be extrapolated to 2-dimensional (2D; films), and in part to 3-dimensional (3D; sponge) systems. Utilizing the C2C12 mouse myoblast cell line as a gold standard, the protocols deliver precise, step-by-step instructions for preparing fiber scaffolds (using silk proteins here), seeding cells, and monitoring key parameters for cultivated meat production, providing a framework for advancing cellular agriculture techniques. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Fabrication and preparation of silk fiber scaffolds for cell seeding Support Protocol 1: Cultivation of C2C12 cells and seeding onto fibrous scaffolds Basic Protocol 2: Quantification of decellularized yarn scaffold degradation during cell culture Basic Protocol 3: Quantification of biomass variation and ECM deposition on yarn scaffolds during C2C12 cell culture Basic Protocol 4: Visualization of cell-laden yarn scaffolds and determination of cell coverage ratio using confocal microscopy Support Protocol 2: Real-time imaging of cell-laden yarn scaffolds using Celigo system Support Protocol 3: Applying green CellTracker fluorescent probes to C2C12 cells seeded on yarn scaffolds.

Fibrin scaffold encapsulated with epigallocatechin gallate microspheres promote neural regeneration and motor function recovery after traumatic spinal cord injury in rats.

Traumatic spinal cord injury (TSCI) is a serious medical issue where there is a loss of sensorimotor function. Current interventions continue to lack the ability to successfully enhance these conditions, therefore, it is crucial to consider alternative effective strategies. Currently, we investigated the effects of fibrin scaffold encapsulated with epigallocatechin gallate (EGCG) microspheres in the recovery of SCI in rats. A total of sixty mature male Sprague-Dawley rats were separated into four groups of the same size: TSCI, fibrin, EGCG, and Fibrin+EGCG. Samples of tissue were gathered at the location of the injury for additional examination. The treatment groups showed significantly higher levels of neurons, antioxidative biomarkers (T-AOC: total antioxidant capacity, GSH: glutathione, and SOD: superoxide dismutase), neurofilament light polypeptide (NEFL) and interleukin 10 (IL-10) genes, and neurological function scores compared to the TSCI group, with the Fibrin+EGCG group displaying the most noticeable improvements. Throughout the treatment process, there was a notable reduction in the amounts of apoptotic and glial cells, as well as levels of malondialdehyde (MDA) and proinflammatory genes (TNF-α: tumor necrosis factor alpha and IL-1β: interleukin-1 beta), especially in the Fibrin+EGCG group compared to the TSCI group. Our findings suggest that EGCG enclosed in microspheres could enhance the prevention of injury spreading and the enhancement of pathological and behavioral symptoms when delivered to the location of spinal cord injury using a fibrin scaffold.

Transformation of Natural Resin Resina Draconis to 3D Functionalized Fibrous Scaffolds for Efficient Chronic Wound Healing (Adv. Healthcare Mater. 30/2024)

Transformation of Natural Resin Resina Draconis to 3D Functionalized Fibrous Scaffolds for Efficient Chronic Wound Healing (Adv. Healthcare Mater. 30/2024)

ACCELERATION HEALING AND OSSEO-INTEGRATION PROCESSES OF CPTI IMPLANT BY COATING TEETH WITH COLLAGEN-POLYCAPROLACTONE FIBER SCAFFOLD

Objective: This study aimed to enhance osseointegration and healing by combining electrospinning techniques with collagen and polycaprolactone (PCL) as a coating for commercial pure titanium (CpTi) implants. Methods: In vitro experiments utilized glacial acetic acid as a solvent system to create collagen/PCL coatings with varying PCL concentrations (10%, 15%, 20% w/v). Morphological and physical characterizations were conducted using scanning electron microscopy (SEM), atomic force microscopy (AFM), and wettability tests. In vivo studies involved implanting collagen/PCL-coated CpTi cylinders into the femoral bone of New Zealand rabbits, followed by histological analysis at 2 and 6 weeks. Results: SEM revealed that scaffolds with higher PCL concentrations exhibited finer nanofiber structures (average diameter: 232 nm) and enhanced hydrophilicity and roughness. Histological analysis demonstrated significant osteogenic activity and basal bone formation, with well-formed bone plates observed at 6 weeks for implants coated with 20% collagen and 20% PCL. Novelty: The study highlights the potential of electrospun collagen/PCL coatings to create optimal surface properties for dental implants, achieving improved tissue integration and healing outcomes. This innovative approach demonstrates the versatility of electrospinning for fabricating fibrous scaffolds that can incorporate therapeutic agents, offering transformative implications for regenerative medicine and implantology.

Construction of Silk Fibroin 3D Microfiber Scaffolds and Their Applications in Anti-Osteoporosis Drug Prediction.

Silk microfiber scaffolds have garnered increasing interest due to their outstanding properties, with degumming being the process used to extract the sericin from the cocoon. In the present study, an attempt to tune the biodegradation period of silk through degumming with various sodium borohydride (NaBH4) concentrations and degumming times was studied. We considered the process, the number of baths used, and the salt concentration. Herein, we report a novel method of expanding microfibers from two-dimensional (2D) to three-dimensional (3D) using a modified gas-foaming technique. Porous three-dimensional (3D) silk fibroin (SF) scaffolds were fabricated by the SF fibers, which were extracted by the NaBH4 degumming method and NaBH4 gas-foaming approach. This study showed that higher salt concentrations, reaching 1.5% in a double bath, effectively removed sericin from silk fibroin, resulting in clean, smooth 3D scaffolds. These scaffolds were then fabricated using a freeze-drying method. The scaffolds were then submerged in solutions containing semen cuscutae (SC) and their surfaces were coated with various percentages of total flavonoids. The scaffolds had no toxicity to the cells in vitro. This work provides a new route for achieving a TFSC-loaded scaffold; it is proved that the coated silk fibroin fiber scaffold has excellent compatibility. Compared with non-drug-loaded silk scaffolds, drug-loaded silk scaffolds promote cell growth.

Portable direct spraying porous nanofibrous membranes stent-loaded polymyxin B for treating diabetic wounds with difficult-to-heal gram-negative bacterial infections

Gram-negative bacteria infections in diabetic wounds are complicated to control, leading to amputation and even death in severe cases. There is an urgent need to develop effective therapeutic strategies. In recent years, electrospinning has attracted much attention due to its resemblance to extracellular matrix (ECM), which can regulate local cellular proliferation, migration, differentiation, etc.; however, its use is limited by its high cost and difficulty in transportation. This study proposes a portable direct-injection porous fibre scaffold containing polymyxin B (PMB) for local slow release for treating diabetic wounds infected with difficult-to-heal Gram-negative bacteria. The handheld portable electrospinner is lightweight and easy to operate and can be directly sprayed in situ to cover wounds with irregular shapes and sizes. When covering the wound in situ, the PVB/PVP nanofiber membrane can protect it from the external environment. Meanwhile, the nanofiber membrane dressing has a porosity of 20 % and a controlled drug-loading capacity. What's more, the evaluation of a whole skin defect model of type II diabetes mellitus infected with Gram-negative bacteria showed that the PMB-loaded nanofiber membrane could effectively inhibit Gram-negative bacteria infection, promote collagen deposition and re-epithelialization, and regulate the polarization of M1-type macrophages to M2-type macrophages, thereby controlling inflammation and promoting vascular regeneration, and significantly accelerating the healing of diabetic wounds. Overall, portable direct-injection porous fibre scaffold-loaded drugs are essential for healing difficult-to-heal wounds as local slow-release drug delivery.

Bioinspired fibrous scaffolds with hierarchical orientations for enhanced spinal cord injury repair

Spinal cord injury (SCI) repair remains a major challenge in regenerative medicine. While biomaterials have shown promise in tissue engineering, they often lack the directional cues necessary to recapitulate the parallel alignment of ascending and descending nerve tracts in the spinal cord at the mesoscale, and to guide axon elongation at the nanoscale, thus limiting their effectiveness in SCI interventions. Within this context, we developed a hydrogel that retains the rapid ionic crosslinking properties of alginate while enhancing its biostability and mechanical strength to support the prolonged process of tissue engineering, achieved by introducing gelatin for covalent crosslinking and incorporating calcium crystallite deposition. The resulting hydrogel can gelatinize within a few seconds and maintain over 60% for 8 weeks in a complete cell medium. Leveraging this gelation strategy, we enabled to further fabricate the hydrogel into a continuous fibrous scaffold by a facile wet-spinning technique. Intriguingly, the obtained micron-sized fibers feature parallel nanoscale grooves on their surface, providing hierarchical guidance cues to mimic spinal cord architecture. Thanks to this multiscale oriented structure, the wet-spun fibers can not only align neural cell distribution but also promote axonal outgrowth in the direction of the fiber axis. When implanted into rats with complete SCI for long-term treatment, the fibrous scaffolds significantly facilitated motor functional recovery, enhanced tissue integration, and markedly improved neural regeneration and neurite extension at the injured sites. Therefore, our study presents a promising strategy for fabricating hierarchically oriented fibers to achieve efficient SCI treatment.

Fabrication of 3D-printed coiled PCL microfibrous bundles using alginate-based biocomposites for bone tissue engineering applications

Abstract Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional (3D) structures conducive to tissue regeneration. Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues. In this study, coiled poly (ϵ-caprolactone) (PCL) fibrous bundles were fabricated using an alginate-based composite system, and processed with 3D printing. The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut, thereby transforming aligned PCL fibers into coiled structures. The effects of printing parameters, such as pneumatic pressure and nozzle moving speed, on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers. The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells (hASCs), supporting its potential in bone tissue engineering.

Engineering Biomimetic Microvascular Capillary Networks in Hydrogel Fibrous Scaffolds via Microfluidics-Assisted Co-Axial Wet-Spinning.

The microvascular bed plays a crucial role in establishing nutrient exchange and waste removal, as well as maintaining tissue metabolic activity in the human body. However, achieving microvascularization of engineered 3D tissue constructs is still an unsolved challenge. In this work, we developed biomimetic cell-laden hydrogel microfibers recapitulating oriented microvascular capillary-like networks by using a 3D bioprinting technique combined with microfluidics-assisted coaxial wet-spinning. Highly packed and aligned bundles embedding a coculture of human bone marrow-derived mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) were produced by simultaneously extruding two different bioinks. To this aim, core-shell fibers were wet-spun in a coagulation bath to collect the scaffolds later on a rotary drum. Initially, the versatility of the proposed system was assessed for the extrusion of multimaterial core-shell hydrogel fibers. Subsequently, the platform was validated for the in vitro biofabrication of samples promoting optimal cell alignment along the fiber axis. After 3 weeks of culture, such fiber configuration resulted in the development of an oriented capillary-like network within the fibrin-based core and in the endothelial-specific CD31 marker expression upon MSC/HUVEC maturation. Synergistically, the vertical arrangement of the coaxial nozzle coupled with the rotation of the fiber collector facilitated the rapid creation of tightly packed bundles characterized by a dense, oriented, and extensively branched capillary network. Notably, such findings suggest that the proposed biofabrication strategy can be used for the microvascularization of tissue-specific 3D constructs.

New biological dressings in diabetic wound healing: Dual effects of anti-infection and immune regulation

Abstract. As a global epidemic, one of the complications of diabetes is chronic difficult heal wounds, especially infectious wounds, which pose a major threat to the quality of life and prognosis of patients. Traditional dressing materials (gauze, film, foam) often have limited effect, and can easily lead to prolonged treatment cycles and antibiotic resistance. In recent years, as an innovative wound management strategy, biological dressings (hydrogels, fiber scaffolds, microneedle patches) have attracted extensive attention due to their antibacterial effect, inhibition of infection, regulation of the body's immune system, promotion of tissue repair, and good biocompatibility. Here, we discuss the impact of diabetes on the body's immune system, tissue cells, and metabolic processes. In addition, we reviewed the specific mechanisms of different biological dressings in the treatment of diabeti-infected wounds. Finally, we discuss current challenges and future research directions.