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High strength and ductility are highly desired in fiber‐reinforced composites, yet achieving both simultaneously remains elusive. A hierarchical architecture is developed utilizing high aspect ratio chemically transformable thermoplastic nanofibers that form covalent bonding with the matrix to toughen the fiber‐matrix interphase. The nanoscale fibers are electrospun on the micrometer‐scale reinforcing carbon fiber, creating a physically intertwined, randomly oriented scaffold. Unlike conventional covalent bonding of matrix molecules with reinforcing fibers, here, the nanofiber scaffold is utilized ‒ interacting non‐covalently with core fiber but bridging covalently with polymer matrix ‒ to create a high volume fraction of immobilized matrix or interphase around core reinforcing elements. This mechanism enables efficient fiber‐matrix stress transfer and enhances composite toughness. Molecular dynamics simulation reveals enhancement of the fiber‐matrix adhesion facilitated by nanofiber‐aided hierarchical bonding with the matrix. The elastic modulus contours of interphase regions obtained from atomic force microscopy clearly indicate the formation of stiffer interphase. These nanoengineered composites exhibit a ≈60% and ≈100% improved in‐plane shear strength and toughness, respectively. This approach opens a new avenue for manufacturing toughened high‐performance composites. [ABSTRACT FROM AUTHOR]

Abstract High strength and ductility are highly desired in fiber‐reinforced composites, yet achieving both simultaneously remains elusive. A hierarchical architecture is developed utilizing high aspect ratio chemically transformable thermoplastic nanofibers that form covalent bonding with the matrix to toughen the fiber‐matrix interphase. The nanoscale fibers are electrospun on the micrometer‐scale reinforcing carbon fiber, creating a physically intertwined, randomly oriented scaffold. Unlike conventional covalent bonding of matrix molecules with reinforcing fibers, here, the nanofiber scaffold is utilized ‒ interacting non‐covalently with core fiber but bridging covalently with polymer matrix ‒ to create a high volume fraction of immobilized matrix or interphase around core reinforcing elements. This mechanism enables efficient fiber‐matrix stress transfer and enhances composite toughness. Molecular dynamics simulation reveals enhancement of the fiber‐matrix adhesion facilitated by nanofiber‐aided hierarchical bonding with the matrix. The elastic modulus contours of interphase regions obtained from atomic force microscopy clearly indicate the formation of stiffer interphase. These nanoengineered composites exhibit a ≈60% and ≈100% improved in‐plane shear strength and toughness, respectively. This approach opens a new avenue for manufacturing toughened high‐performance composites.

Pulp-Dentin regeneration is a key aspect of maintain tooth vitality and enabling good oral-systemic health. This study aimed to investigate a nanofibrous scaffold loaded with a small molecule i.e. Tideglusib to promote odontogenic differentiation. Tideglusib (GSK-3β inhibitor) interaction with GSK-3β was determined using molecular docking and stabilization of β-catenin was examined by confocal microscopy. 3D nanofibrous scaffolds were fabricated through electrospinning and their physicochemical characterizations were performed. Scaffolds were seeded with mesenchymal stem cells or pre-odontoblast cells to determine the cells proliferation and odontogenic differentiation. Our results showed that Tideglusib (TG) binds with GSK-3β at Cys199 residue. Stabilization and nuclear translocation of β-catenin was increased in the odontoblast cells treated with TG. SEM analysis revealed that nanofibers exhibited controlled architectural features that effectively mimicked the natural ECM. UV-Vis spectroscopy demonstrated that TG was incorporated successfully and released in a controlled manner. Both kinds of biomimetic nanofibrous matrices (PCLF-TG100, PCLF-TG1000) significantly stimulated cells proliferation. Furthermore, these scaffolds significantly induced dentinogenic markers (ALP, and DSPP) expression and biomineralization. In contrast to current pulp capping material driving dentin repair, the sophisticated, polymeric scaffold systems with soluble and insoluble spatiotemporal cues described here can direct stem cell differentiation and dentin regeneration. Hence, bioactive small molecule-incorporated nanofibrous scaffold suggests an innovative clinical tool for dentin tissue engineering. Graphical Abstract [ABSTRACT FROM AUTHOR]

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol–gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems. [ABSTRACT FROM AUTHOR]

Electrospun fibers, with proven ability to promote tissue regeneration, are widely being explored for rotator cuff repairing. However, without post treatment, the microstructure of the electrospun scaffold is vastly different from that of natural extracellular matrix (ECM). Moreover, during mechanical loading, the nanofibers slip that hampers the proliferation and differentiation of migrating stem cells. Here, electrospun nanofiber scaffolds, with crimped nanofibers and welded joints to biomimic the intricate natural microstructure of tendon-to-bone insertion, were prepared using poly(ester-urethane)urea and gelatin via electrospinning and double crosslinking by a multi-bonding network densification strategy. The crimped nanofiber scaffold (CNS) features bionic tensile stress and induces chondrogenic differentiation, laying credible basis for in vivo experimentation. After repairing a rabbit massive rotator cuff tear using a CNS for 3 months, the continuous translational tendon-to-bone interface was fully regenerated, and fatty infiltration was simultaneously inhibited. Instead of micro-CT, μCT was employed to visualize the integrity and intricateness of the three-dimensional microstructure of the CNS-induced-healed tendon-to-bone interface at an ultra-high resolution of less than 1 μm. This study sheds light on the correlation between nanofiber post treatment and massive rotator cuff repair and provides a general strategy for crimped nanofiber preparation and tendon-to-bone interface imaging characterization.

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. [ABSTRACT FROM AUTHOR]

Synthetic peptides are promising structural and functional components of bioactive and tissue-engineering scaffolds. Here, we demonstrate the design of self-assembling nanofiber scaffolds based on peptide amphiphile (PA) molecules containing multi-functional histidine residues with trace metal (TM) coordination ability. The self-assembly of PAs and characteristics of PA nanofiber scaffolds along with their interaction with Zn, Cu, and Mn essential microelements were studied. The effects of TM-activated PA scaffolds on mammalian cell behavior, reactive oxygen species (ROS), and glutathione levels were shown. The study reveals the ability of these scaffolds to modulate adhesion, proliferation, and morphological differentiation of neuronal PC-12 cells, suggesting a particular role of Mn(II) in cell-matrix interaction and neuritogenesis. The results provide a proof-of-concept for the development of histidine-functionalized peptide nanofiber scaffolds activated with ROS- and cell-modulating TMs to induce regenerative responses. [ABSTRACT FROM AUTHOR]

Electrospun nonwovens have great potential for biomedical applications. They can be used, for example, to mimic the structure of the extracellular matrix of biological tissue. In this work, it is demonstrated that the surface properties of nanofiber nonwovens made of biocompatible and very slowly biodegrading polyamide can be modified by UV picosecond laser processing. Basically, the nanofiber structure is only slightly changed by the corresponding laser process. Significant laser‐induced material change occurs only along narrow lines determined by the scanning process. The newly formed surface structures resemble a bulk surface. It is shown that the growth of mammalian chondrocyte cells (SW1353) is initially more effective on the laser‐processed surface. Cell growth occurs preferably along the laser‐generated lines. After several days of cell growth, an extended layer of cells is formed over the laser‐modified and unmodified surface sections. Thus, laser‐based surface modification provides another tool to affect cell proliferation on polyamide nanofiber nonwovens. [ABSTRACT FROM AUTHOR]

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol–gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.

Synthetic peptides are promising structural and functional components of bioactive and tissue-engineering scaffolds. Here, we demonstrate the design of self-assembling nanofiber scaffolds based on peptide amphiphile (PA) molecules containing multi-functional histidine residues with trace metal (TM) coordination ability. The self-assembly of PAs and characteristics of PA nanofiber scaffolds along with their interaction with Zn, Cu, and Mn essential microelements were studied. The effects of TM-activated PA scaffolds on mammalian cell behavior, reactive oxygen species (ROS), and glutathione levels were shown. The study reveals the ability of these scaffolds to modulate adhesion, proliferation, and morphological differentiation of neuronal PC-12 cells, suggesting a particular role of Mn(II) in cell-matrix interaction and neuritogenesis. The results provide a proof-of-concept for the development of histidine-functionalized peptide nanofiber scaffolds activated with ROS- and cell-modulating TMs to induce regenerative responses.

In this study, soybean protein nanoparticles (SPN) modified poly(hydroxybutyrate) (PHB) electrospun nanofiber scaffold is fabricated by a facile two-step method combination of PHB electrospinning and SPN evaporation-induced self-assembly. The surface characteristics, structure and properties are investigated by SEM, EDS, XPS, FTIR, XRD, DMA, WCA, tensile test and water uptake capacity measurements. To characterize biodegradability and cytocompatibility, biodegradation tests are performed in simulated body fluid with and without lysozyme and cell cultures are carried out using NIH3T3 mouse fibroblast cells by in vitro studies. The as-obtained SPN-modified PHB nanofiber scaffold presents better cytocompatibility and is more suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

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.

The paper describes the synthesis of hydroxyapatite (HAp) and strontium-substituted hydroxyapatite (SrHAp) from sand lobster shells by a hydrothermal method. The HAp and SrHAp were incorporated into the polyvinyl alcohol (PVA) nanofiber scaffold through the eletrospinning method. The scaffolds were incorporated with 5wt% of hydroxyapatite (HAp), 5wt%, 10wt%, and 15% of SrHAp. The physicochemical, mechanical, and in vitro biological properties of the scaffold were evaluated. The incorporation of HAp or SrHAp was evidenced by the diffraction patterns and the phosphate functional groups related to HAp. The morphological results showed the decrement of fiber diameter in line with the increased SrHAp concentration. A tensile test was conducted to investigate the mechanical properties of the scaffolds, and the results showed that the scaffolds perform poorly at a higher SrHAp concentration because of exceeding agglomeration levels. The PVA/SrHAp15 performed the best antibacterial activity against E. coli and S. aureus with an inhibition zone of (15.2 ± 0.2) and (14.5 ± 0.8), respectively. The apatite formation was more abundant in PVA/SrHAp10 after immersion in a simulated body fluid (SBF). Cell viability results showed that the scaffold enabled the osteoblast cells to grow and proliferate. The biocompatibility of HAp and SrHAp resulted in the enhancement of cell adhesion. Based on all tests, the PVA/SrHAp 10 scaffold shows a strong candidate for further in vivo studies., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Polyvinyl alcohol (PVA), as an important polymeric material, has various applications in industry and medicine. The present study investigated these nanofibers' mechanical properties, including modulus of elasticity (MOE), the adhesion between them and the atomic force microscope probe. The study used an electrospinning system to synthesize PVA nanofibers with different concentrations as well as aligned and random scaffold assemblies. The effect of different concentrations and nanofiber scaffold assemblies on the MOE and adhesion was investigated for the extension and retraction strokes in JPK SPM. The results showed that increasing the PVA concentration increased the MOE but decreased adhesion. Considering the random format of PVA nanofiber scaffolds, the increasing MOE rate and decreasing adhesion rate due to increasing PVA concentration are, respectively, 0.097 Mpa (PVA Concentration %) - 1 and 1.868 Nn (PVA Concentration %) - 1 for extension stroke and for retraction stroke are 0.255 Mpa (PVA Concentration %) - 1 and 4.75 Nn (PVA Concentration %) - 1 . Moreover, using the aligned nanofiber format reduced the MOE, and the adhesion was greater for the retraction strokes than extension strokes, while the situation was reversed for the MOE. Finally, in nanofibers with random format scaffolds, increasing the PVA concentration increased the diameter of the nanofibers. The increasing rate of average nanofiber diameters by increasing PVA concentration is 89.424 nm (PVA Concentration %) - 1 for random and aligned scaffolds. [ABSTRACT FROM AUTHOR]

Mechanical loading influences on the chondrocyte and may promote articular cartilage repair in vivo. That is thought to play a key role in the differentiation of MSCs and in tissue healing and repair. We aimed to evaluate the effect of mechanical Loading of walking on articular cartilage repair. So the stem cells were isolated from the infrapatellar adipose tissue and were seeded on PCL. Then cell-scaffold constructs were sputter-coated with gold and observed by scanning electron microscopy to determine the adhesion of ASCs on the scaffold. ASCs-PCL constructs were transplanted into defects in sheep knees then ASCs on the scaffold was induced by the mechanical loading in vivo. Repaired tissue was evaluated with Q(RT-PCR), immunofluorescence staining, toluidine blue staining and Masson's trichrome staining, the results revealed the largest areas of type II collagen staining, Sox9 expression, aggrecan and presence of chondrocytes in repaired cartilage in experimental groups. Also, the results of this study suggest that mechanical loading of walking could be used to induce ASCs to repair articular cartilage in vivo. [ABSTRACT FROM AUTHOR]

Critical-sized segmental long bone defects represent a challenging clinical dilemma in the management of battlefield and trauma-related injuries. The residual bone marrow cavity of damaged long bones contains many bone marrow mesenchymal stem cells (BMSCs), which provide a substantial source of cells for bone repair. Thus, a three-dimensional (3D) vertically aligned nanofiber scaffold (VAS) is developed with long channels and large pore size. The pore of VAS toward the bone marrow cavity after transplantation, enables the scaffolds to recruit BMSCs from the bone marrow cavity to the defect area. In vivo, it is found that VAS can significantly shorten gap distance and promote new bone formation compared to the control and collagen groups after 4 and 8 weeks of implantation. The single-cell sequencing results discovered that the 3D nanotopography of VAS can promote BMSCs differentiation to chondrocytes and osteoblasts, and up-regulate related gene expression, resulting in enhancing the activities of bone regeneration, endochondral ossification, bone trabecula formation, bone mineralization, maturation, and remodeling. The Alcian blue and bone morphogenetic protein 2 (BMP-2) immunohistochemical staining verified significant cartilage formation and bone formation in the VAS group, corresponding to the single-cell sequencing results. The study can inspire the design of next-generation scaffolds for effective long-bone regeneration is expected by the authors., (© 2024 Wiley‐VCH GmbH.)

Nanofiber scaffolds provide numerous advantages over common carriers engineered for microorganisms. The most important advantage is an increased speed of primary surface colonization (up to four times faster), which shortens the time required for the areal biofilm formation and optimum performance of attached microorganisms (higher efficiency of biological activity of up to twice as fast). Image analysis predicts early formation of biofilm even in beginning stages; analysis of biofilm reveals the different structures of bacterial colonies on both scaffolds (higher porosity, size, and number of bacterial colonies on nanofiber's surface). The image analysis correlates well with determinations of dry matter (linear correlation of 0.96) and proteins (linear correlation of 0.89). [ABSTRACT FROM AUTHOR]

Implants or cell carriers made of biopolymers or biodegradable polymers are well suited for the regeneration of defects in various tissues. They act as an adhesion surface for autologous cells and provide sufficient stability. Electrospun nonwovens have a favourable surface to volume ratio and mimic the structure of the fiber proteins of the extracellular matrix in tissues. Their high porosity ensures a sufficient supply of nutrients to the cells while maintaining high mechanical strength. In addition, drug-release functionality can be installed in biodegradable nonwovens, which can support the regeneration. Particularly promising are flakes made of electrospun nonwovens which, in an appropriate suspension, can be injected into defective areas. For the production of such flakes, laser cutting or surface structuring can be applied. Typically, ablation by ultrashort laser pulses reduces the heat-affected zones significantly in microprocessing of many polymers. In this work, the quality of processing of electrospun gelatine and poly-lactide (PLA) nonwovens was investigated for UV-solidstate lasers with pulse durations in the nano- and picosecond range. We observed comparable ablation quality of electrospun gelatine nonwovens with UV nanosecond and with UV picosecond ablation. A similar behaviour was found for electrospun PLA nonwovens. Higher pulse energy was necessary for nanosecond ablation with the same focal spot diameter. [ABSTRACT FROM AUTHOR]

Full-thickness skin defect is one of the main clinical problems, which cannot be repaired spontaneously. The aim of this study was to evaluate the feasibility of combining nanofibers with ADM as a bilayer scaffold for treatment of full-thickness skin wounds in a single-step procedure. The nanofibrous polycaprolactone/fibrinogen scaffolds were fabricated by electrospinning. Subsequently, mesenchymal stem cells were isolated from rat adipose tissues and characterized by flow cytometry. Cell adhesion, proliferation, and the epidermal differentiation potential of adipose-derived stem cells (ADSCs) on nanofibrous scaffolds were investigated by scanning electron microscopy (SEM), alamarBlue, and real-time PCR, respectively. In animal studies, full-thickness excisional wounds were created on the back of rats and treated with following groups: ADM, ADM-ADSCs, nanofiber, nanofiber-ADSCs, bilayer, and bilayer-ADSCs. In all groups, wounds were harvested on days 14 and 21 after treatment to evaluate re-epithelialization, blood vessel density, and collagen content. The results indicated that ADSCs seeded on ADM, nanofiber, and bilayer scaffolds can promote re-epithelialization, angiogenesis, and collagen remodeling in comparison with cell-free scaffolds. In conclusion, nanofiber-ADSCs showed the best results for re-epithelialization (according to histological scoring), average blood vessel density (92.7 ± 6.8), and collagen density (87.4 ± 4.9%) when compared to the control and other experimental groups. [ABSTRACT FROM AUTHOR]

In this study, a system of dexamethasone sodium phosphate (DEXP)-loaded chitosan nanoparticles embedded in poly-e-caprolacton (PCL) and gelatin electrospun nanofiber scaffold was introduced with potential therapeutic application for treatment of the nervous system. Besides anti-inflammatory properties, DEXP act through its glucocorticoid receptors, which are involved in the inhibition of astrocyte proliferation and microglial activation. Bovine serum albumin (BSA) was used to improve the encapsulation efficiency of DEXP within chitosan nanoparticles and to overcome its initial burst release. BSA incorporation within the chitosan nanoparticles increased the encapsulation efficiency of DEXP from 30% to 77%. The comparison between DEXP release profile from PCL/gelatin scaffold with and without chitosan nanoparticles revealed that the system of DEXP-BSA-loaded chitosan nanoparticles embedded in electrospun PCL nanofiber scaffold provided a more controlled release pattern of the loaded drug. The scaffolds properties in terms of structure, hydrophilicity, cell compatibility, mechanical property, and biodegradability were further investigated, which might show its potential application for the repair of spinal cord injury. [ABSTRACT FROM AUTHOR]

• PGCC enhances wound healing using piezoelectric and photothermal functionalities. • PGCC with CaO 2 treats chronic hypoxia by converting ROS into molecular O 2. • The wound dressing exhibited ∼ 10 % (E. coli) and ∼ 13 % (S. aureus) survival rates. • US and NIR radiation synergistically enhance wound recovery by ∼ 1.5 folds in vivo. The process of wound healing is often obstructed by the prevalence of bacterial infection at the wound site. Hence, innovative strategies to alleviate infection is extremely necessary to realize effective wound recovery in a timely manner. Here, we report a self-activated composite dressing consisting of piezoelectric and photothermal functional layers for combating wound infection and provide the desired treatment. The synergistic dressing is functionalized with piezoelectric Poly-L-lactic acid (PLLA) which under the effect of ultrasound irradiation controllably generates reactive oxygen species (ROS) for antibacterial activity, thus facilitating the dressing to inhibit the growth of bacteria at the wound bed. Further, the dressing is modified with calcium peroxide (CaO 2) which can effectively convert the generated ROS into molecular oxygen (O 2) in presence of catalase enzyme for treating chronic hypoxia in the infected wounds. The sustained generation of O 2 by the wound dressing augmented the cell proliferation, migration and tissue regeneration aiding in wound healing. By combining the inherent photothermal activity of reduced graphene oxide (rGO), the synergistic dressing under NIR irradiation enhanced the wound recovery by upregulating the heat shock protein 90 (Hsp90) secretion owing to the heat generation on the wounds. The results obtained demonstrate that the self-triggered multifunctional wound dressing is a promising candidate for clinical treatment of infected wounds with a user-friendly interface. [ABSTRACT FROM AUTHOR]

Electrospun nanofiber scaffolds of different polymers are used in tissue engineering to mimic the extracellular matrices with favourable conditions for cell growth and proliferation. Structures such as cavities, holes and cuts in the scaffolds can be used to optimize cell growth. We investigated the influence of different laser sources used for direct laser writing on the cutting and structuring quality of electrospun polyamide nonwovens. Ablation thresholds and rates were determined. Because of different approaches in cell colonization with scaffolds, the investigations were carried out on dry, wet and immersed nonwovens. The results show that femto- and picosecond lasers are very well suited for processing of dry nonwovens. Processing with green wavelengths is more effective and leads to similar minimum feature sizes than in the ultraviolet range. Ablation rates up to 8000 μm³/pulse were obtained which are about a factor of 100 higher than those for polyamide bulk material. Nanosecond UV lasers produced structures of reduced quality. Excimer lasers at 193 nm offer a possible alternative for large-area structures when operated at low fluences. Processing of wet and immersed nanofibers is possible with smaller processing speed and with a slightly degraded quality. [ABSTRACT FROM AUTHOR]

A straightforward, fast, and versatile technique is developed to fabricate nanofibrous scaffold with excellent hydrophilicity, mechanical properties, and biocompatibility for tissue engineering. The thermoplastic polyurethane (TPU) nanofiber is fabricated by utilizing electrospinning, and then its surface is modified through simply immersing it into cellulose nanofibrils (CNF) dispersion and subjecting to ultrasonication. The results show that the CNF particles are successfully absorbed on the surface of TPU nanofiber. By introducing CNF particles on the surface of TPU nanofiber, the hydrophilicity, mechanical properties of fabricated CNF-absorbed TPU scaffold are significantly increased. Additionally, the adhesion and proliferation of human umbilical vein endothelial cells cultured on CNF-absorbed TPU scaffold are prominently enhanced in comparison with those of cultured on TPU scaffold. These findings suggest that the ultrasound-assisted technique opens up a new way to simply and effectively modify the surface of various scaffolds and the modified scaffold could be shown a great potential in tissue engineering. [ABSTRACT FROM AUTHOR]

Biphasic materials, comprised of an ordered arrangement of two different material phases within a material, have the potential for a wide variety of applications including filtration, protective clothing and tissue engineering. This study reports for the first time, a process for engineering biphasic Janus-type polymeric nanofiber (BJPNF) networks via the centrifugal jet spinning technique. BJPNF alignment and fiber diameter was dependent on fabrication rotational speed as well as solution composition. The biphasic character of these BJPNFs, which was controlled via the rotational speed of fabrication, was confirmed at the individual nanofiber scale using energy dispersive X-ray spectroscopy, and at the bulk, macro-scale using attenuated total reflectance-Fourier transform infrared spectroscopy. Biphasic character was also demonstrated at the functional level via differing affinities on either side of the BJPNF for cell attachment. Our work thus presents a method for fabricating BJPNF scaffold networks where there might be a need for different properties on either side of a material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2455-2464, 2017. [ABSTRACT FROM AUTHOR]

Recent trends in tissue engineering have focused on the development of electrically conductive composite scaffolds (i.e. with carbon nanotubes) and on increasing the cell interaction of electrospun synthetic polymers by means of incorporation of biological molecules (i.e. via functionalition with polydopamine). In this study the electrospinning process was first optimized for the processing of poly(ε-caprolactone) and the use of formic acid allowed mats of 100–200 nm nanofibers with (0.5% of CNT) or without CNT to be created. Then, the PCL nanofibers were successfully coated by a polydopamine layer of approximately 15 nm thick, confirmed by XPS analysis and SEM images. This coating did not add mechanical strength and decreased the Young’s modulus of the mats from 25.5 MPa to 13.6 MPa at 21 °C. Consequently, the PCL-PDA coated scaffolds showed higher deformation values when the equilibrium was reached (13.7%) during the fatigue tests (at 37 °C in aqueous medium, 0.5 MPa of stress) under conditions that simulate the heart beats (1 Hz), experiments in which both PCL and the modified mats (with PDA or CNT) exhibited a fatigue life of more than 10 6 cycles. However, at a cyclic stress of 1.5 MPa the PDA treated mats underwent fatigue failures by plastic deformation while those of non-modified PCL failed after partial tearing (only 40% of them exceeded 10 3 cycles). The incorporation of CNTs within the PCL fibers was confirmed by TEM and improved the fatigue performance by means of preventing the fraying of the fibers (80% of the specimens reached at least 10 3 cycles). Both the PDA layer and the presence of embedded stiff carbon nanotubes, hindered fiber orientation in the tensile tests and their elongation at break were lower than those of PCL scaffolds. [ABSTRACT FROM AUTHOR]

Considering the important factor of bioactive nanohydoxyapatite (nHA) to enhance osteoconductivity or bone-bonding capacity, nHA was incorporated into an electrospun polycaprolactone (PCL) membrane using electrospinning techniques. The viscosity of the PCL and nHA/PCL with different concentrations of nHA was measured and the morphology of the electrospun membranes was compared using a field emission scanning electron microscopy. The water contact angle of the nanofiber determined the wettability of the membranes of different concentrations. The surface roughness of the electrospun nanofibers fabricated from pure PCL and nHA/PCL was determined and compared using atomic force microscopy. Attenuated total reflectance Fourier transform infrared spectroscopy was used to study the chemical bonding of the composite electrospun nanofibers. Beadless nanofibers were achieved after the incorporation of nHA with a diameter of 200-700 nm. Results showed that the fiber diameter and the surface roughness of electrospun nanofibers were significantly increased after the incorporation of nHA. In contrast, the water contact angle (132° ± 3.5°) was reduced for PCL membrane after addition of 10% (w/w) nHA (112° ± 3.0°). Ultimate tensile strengths of PCL membrane and 10% (w/w) nHA/PCL membrane were 25.02 ± 2.3 and 18.5 ± 4.4 MPa. A model drug tetracycline hydrochloride was successfully loaded in the membrane and the membrane demonstrated good antibacterial effects against the growth of bacteria by showing inhibition zone for E. coli (2.53 ± 0.06 cm) and B. cereus (2.87 ± 0.06 cm). [ABSTRACT FROM AUTHOR]

The capacity of gelatin/chitosan/bioactive glass nanopowders (GEL/CS/BGNPs) scaffolds was investigated for increasing human endometrial stem cells (hEnSCs) differentiation into the endothelial cells in the presence of angiogenic factors. GEL/CS nanofibrous scaffold with different contents of BGNPs were fabricated and assessed. Expression of endothelial markers (CD31, vascular endothelial cadherin (VE-cadherin), and KDR) in differentiated cells was evaluated. Results showed the diameter of nanofiber increases with decreasing the BG content in GEL/CS scaffolds. Moreover,in vitrostudy indicated that the GEL/CS/BGNPs scaffold with 1.5% BGNPs content provided a suitable three-dimensional structure for endothelial cells differentiation. Thus, the GEL/CS/BGNPs scaffold can be recommended for blood vessels repair. [ABSTRACT FROM AUTHOR]

Bone fractures are often companied with poor bone healing and high rates of infection. Early recruitment of mesenchymal stem cells (MSCs) is critical for initiating efficient bone repair, and mild thermal stimulation can accelerate the recovery of chronic diseases. Here, a bioinspired, staged photothermal effect-reinforced multifunctional scaffold was fabricated for bone repair. Uniaxially aligned electrospun polycaprolactone nanofibers were doped with black phosphorus nanosheets (BP NSs) to endow the scaffold with excellent near-infrared (NIR) responsive capability. Apt19S was then decorated on the surface of the scaffold to selectively recruit MSCs toward the injured site. Afterward, microparticles of phase change materials loaded with antibacterial drugs were also deposited on the surface of the scaffold, which could undergo a solid-to-liquid phase transition above 39 °C, triggering the release of payload to eliminate bacteria and prevent infection. Under NIR irradiation, photothermal-mediated up-regulation of heat shock proteins and accelerated biodegradation of BP NSs could promote the osteogenic differentiation of MSCs and biomineralization. Overall, this strategy shows the ability of bacteria elimination, MSCs recruitment, and bone regeneration promotion with the assistance of photothermal effect in vitro and in vivo , which emphasizes the design of a bioinspired scaffold and its potential for a mild photothermal effect in bone tissue engineering.

Extracellular matrix (ECM) structure and biochemistry provide cell-instructive cues that promote and regulate tissue growth, function, and repair. From a structural perspective, the ECM is a scaffold that guides the self-assembly of cells into distinct functional tissues. The ECM promotes the interaction between individual cells and between different cell types, and increases the strength and resilience of the tissue in mechanically dynamic environments. From a biochemical perspective, factors regulating cell–ECM adhesion have been described and diverse aspects of cell–ECM interactions in health and disease continue to be clarified. Natural ECMs therefore provide excellent design rules for tissue engineering scaffolds. The design of regenerative three-dimensional (3D) engineered scaffolds is informed by the target ECM structure, chemistry, and mechanics, to encourage cell infiltration and tissue genesis. This can be achieved using nanofibrous scaffolds composed of polymers that simultaneously recapitulate 3D ECM architecture, high-fidelity nanoscale topography, and bio-activity. Their high porosity, structural anisotropy, and bio-activity present unique advantages for engineering 3D anisotropic tissues. Here, we use the heart as a case study and examine the potential of ECM-inspired nanofibrous scaffolds for cardiac tissue engineering. We asked: Do we know enough to build a heart ? To answer this question, we tabulated structural and functional properties of myocardial and valvular tissues for use as design criteria, reviewed nanofiber manufacturing platforms and assessed their capabilities to produce scaffolds that meet our design criteria. Our knowledge of the anatomy and physiology of the heart, as well as our ability to create synthetic ECM scaffolds have advanced to the point that valve replacement with nanofibrous scaffolds may be achieved in the short term, while myocardial repair requires further study in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Background The aim of this study was the ex vivo expansion of Umbilical Cord Blood hematopoietic stem cells on biocompatible nanofiber scaffolds. Materials and Methods CD133+ hematopoietic stem cells were separated from umbilical cord blood using MidiMacs (positive selection) system by means of monocolonal antibody CD133 (microbeads); subsequently, flowcytometry method was done to assess the purity of separated cells. Isolated cells were cultured on plate (2 Dimensional) and fibronectin conjugated polyethersulfon nanofiber scaffold, simultaneously (3 Dimensional). Colony assay test was performed to show colonization ability of expanded cells. Results Cell count analysis revealed that expansion of hematopoietic stem cells in 2dimensional (2D) environment was greater than 3dimensional (3D) condition (p= 0.01). Assessment of stem cellphenotype after expansions was performed by flowcytometric analysis which is showed that the maintenance of CD133 marker in expanded cells in 3 dimensional condition were higher than expanded cells in 2 dimensional condition (p=0.01). Moreover, colony assay test was performed before and after of expansion to show colonization ability of expanded cells both in 3D and 2D culture and results revealed more ability of 3D culture compared with 2D culture (p= 0.03). Conclusion The results of current study confirmed that umbilical cord blood CD133+ haematopoietic stem cells are able to expand on fibronectin conjugated polyethersulfon scaffold. These findings indicated that 3D is a proper and valuable cell culture system for hematopoietic stem cells expansion, compared to 2D in invitro situation. [ABSTRACT FROM AUTHOR]

The hydrophilicity of the extracellular matrix is one of the most important factors affecting cell adhesion in tissue engineering. In the present study, to improve the cellular biocompatibility of poly( ε -caprolactone) (PCL) nanofiber scaffolds, their surface hydrophilicity was enhanced by electrospinning PCL with biocompatible, amphiphilic poly( N -vinylpyrrolidone)- b -PCL (PVP- b -PCL) block copolymer. The PVP- b -PCL block copolymer ( M n = 26,300 g/mol, M w / M n = 1.14) was synthesized using 2-hydroxyethyl 2-(ethoxycarbonothioylthio)propanoate as a dual initiator for reversible addition–fragmentation chain transfer polymerization and ring opening polymerization in a one-pot procedure. As the content of PVP- b -PCL block copolymer increased, the surface of the PCL/PVP- b -PCL nanofiber scaffolds became more hydrophilic. The scaffolds showed no cytotoxicity, better cell adhesion, and improved viability of primary fibroblasts than PCL scaffolds, and did not lose their structure during cell culture. In particular, the PCL/PVP- b -PCL (90/10, w/w) nanofiber scaffold produced the highest cell viability, suggesting that appropriate scaffold hydrophilicity is required to enhance cell activity. [ABSTRACT FROM AUTHOR]

Abstract: LST28 nanofibers prepared by electrospinning can be sintered on ScSZ electrolyte at 1000 °C without formation of secondary phase. LST28 nanofibers with an electronic conduction pathway on ScSZ electrolyte provide an efficient anchoring scaffold for the infiltrated Gd0.2Ce0.8O1.9 (GDC). The microstructure morphology and elemental distributions of Gd0.2Ce0.8O1.9–La0.2Sr0.8TiO3 (GDC–LST28) have been investigated in detail. GDC greatly improves the electrochemical performance of the fuel electrode. GDC–LST28 (0.92:1) composite anode gives the low interfacial polarization resistances (R P) of 0.95, 0.63, 0.38 and 0.27 Ω cm2 at 800, 850, 900 and 950 °C, respectively. The adding of GDC has greater influence on reducing low frequency region resistance of the polarization resistance than high frequency region resistance. The fuel cell with the GDC–LST28 composite anode has good thermal cycling stability. [Copyright &y& Elsevier]

Abstract: Cellular microenvironments are important in coaxing cells to behave collectively as functional, structured tissues. Important cues in this microenvironment are the chemical, mechanical and spatial arrangement of the supporting matrix in the extracellular space. In engineered tissues, synthetic scaffolding provides many of these microenvironmental cues. Key requirements are that synthetic scaffolds should recapitulate the native three-dimensional (3D) hierarchical fibrillar structure, possess biomimetic surface properties and demonstrate mechanical integrity, and in some tissues, anisotropy. Electrospinning is a popular technique used to fabricate anisotropic nanofiber scaffolds. However, it suffers from relatively low production rates and poor control of fiber alignment without substantial modifications to the fiber collector mechanism. Additionally, many biomaterials are not amenable for fabrication via high-voltage electrospinning methods. Hence, we reasoned that we could utilize rotary jet spinning (RJS) to fabricate highly aligned hybrid protein-polymer with tunable chemical and physical properties. In this study, we engineered highly aligned nanofiber constructs with robust fiber alignment from blends of the proteins collagen and gelatin, and the polymer poly-ε-caprolactone via RJS and electrospinning. RJS-spun fibers retain greater protein content on the surface and are also fabricated at a higher production rate compared to those fabricated via electrospinning. We measured increased fiber diameter and viscosity, and decreasing fiber alignment as protein content increased in RJS hybrid fibers. RJS nanofiber constructs also demonstrate highly anisotropic mechanical properties mimicking several biological tissue types. We demonstrate the bio-functionality of RJS scaffold fibers by testing their ability to support cell growth and maturation with a variety of cell types. Our highly anisotropic RJS fibers are therefore able to support cellular alignment, maturation and self-organization. The hybrid nanofiber constructs fabricated by RJS therefore have the potential to be used as scaffold material for a wide variety of biological tissues and organs, as an alternative to electrospinning. [Copyright &y& Elsevier]

Objective: This project's primary purpose was to create engineered vascular scaffolds using polyurethane, polycaprolactone, and pullulan polymers, along with suitable mechanical-dynamic conditions. Therefore, electrospun scaffolds with optimized intrinsic physiological properties and the ability to support endothelial cells were prepared in vitro, and cell viability was studied in PCL-PU and PCL-PU scaffolds containing Pullulan., The Main Methods: The electrospinning method has been used to prepare PCL-PU and PCL-PU scaffolds containing Pullulan. The scaffold's surface morphology was evaluated using SEM microscopic imaging. The scaffolds' physicochemical properties were prepared using ATR-FTIR, strain stress, and water contact angle tests, and the biocompatibility of PCL-PU and PU-PCL-Pl nanofibers was evaluated using the MTT test., Principal Findings: The test results showed that PCL-PU scaffolds containing Pullulan have more suitable mechanical properties such as stress-strain, water contact angle, swelling rate, biocompatibility, fiber diameter, and pore size compared to PU-PCL. The culture of endothelial cells under static conditions on these scaffolds did not cause cytotoxic effects under static conditions compared to the control group. SEM images confirmed the ability of endothelial cells to attach to the scaffold surface., Summary and Conclusion: The results showed that PCL-PU substrate containing pullulan could stimulate endothelial cells' proliferation under static conditions.

Abstract: Peripheral nerve injury still remains a refractory challenge for both clinical and basic researchers. A novel nanofiber conduit made of blood vessel and filled with amphiphilic hydrogel of self-assembling nanofiber scaffold (SAPNS) was implanted to repair a 10 mm nerve gap after sciatic nerve transection. Empty blood vessel conduit was implanted serving as control. Results showed that this novel nanofiber conduit enabled the peripheral axons to regenerate across and beyond the 10 mm gap. Motoneuron protection, axonal regeneration and remyelination were significantly enhanced with SAPNS scaffold treatments. The target reinnervation and functional recovery induced by the regenerative nerve conduit suggest that SAPNS-based conduit is highly promising application in the treatment of peripheral nerve defect. From the Clinical Editor: In this paper by Zhan et al, a novel self-assembling nanofiber scaffold is reported to promote regeneration of peripheral nerves in a sciatic nerve injury model. The promising results and the obvious medical need raises hope for a clinical translation of this approach hopefully in the near future. [Copyright &y& Elsevier]

Abstract: The diseases of the esophagus include congenital defects like atresia, tracheoesophageal fistula as well as others such as gastro-esophageal reflux disease (GERD), Barrett''s esophagus, carcinoma and strictures. All esophageal disorders require surgical intervention and reconstruction with appropriate substitutes. Primary anastomosis is used to treat most cases but treatment of long gap atresia still remains a clinical challenge. Autologous graft therapies using tissues from colon, and small and large intestine or gastric transplantations have been attempted but have constraints like leakage, infection and stenosis at the implanted site, which leads to severe morbidity and mortality. An alternative for autologous grafts are allogenic and xenogenic grafts, which have better availability but disease transmission and immunogenicity limit their applications. Use of biodegradable and biocompatible scaffolds to engineer the esophagus promises to be an effective regenerative strategy for treatment of esophageal disorders. Nanotopography of the fibrous scaffolds mimics the natural extracellular matrix (ECM) of the tissue and incorporation of chemical cues and tailoring mechanical properties provide the right microenvironment for co-culture of different cell types. Scaffolds cultured with esophageal cells (epithelial cells, fibroblast and smooth muscle cells) might show enhancement of the biofunctionality in vivo. This review attempts to address the various strategies and challenges involved in successful tissue engineering of the esophagus. [Copyright &y& Elsevier]

The poor survival and differentiation of the donor cells in the infarcted myocardium has hampered the therapeutic efficacy of cell transplantation. A self-assembling polypeptide RAD16-II (Ac-RARADADARARADADA-CONH2) spontaneously assembles into stable nanofiber scaffolds, which mimic natural extracellular matrix at 0.1-1% peptide concentrations in the myocardium. We isolated mesenchymal stem cells from the bone marrow of adult male rats that express both c-kit and Nkx2.5, a cardiac transcription factor, yielding selected mesenchymal stem cells (SMSCs). We initially confirmed that the self-assembling polypeptide scaffolds are conducive to growth, survival and differentiation of SMSCs in vitro. Subsequently, SMSCs mixed with the self-assembling polypeptide were injected into the infarcted area at 30 min after the establishment of myocardial infarction in female rats. The donor cells were tracked with Y chromosome in the myocardium. The changes of cardiac function, myocardial structure and capillary density were detected at 4 weeks after cell transplantation. The hearts transplanted with SMSCs incorporated into the nanofiber scaffolds showed smaller infarction size (19.55 ± 2.1%) than the hearts injected with SMSCs (27.37 ± 4.8%). Importantly, the systolic function indices, left ventricle ejection fraction and left ventricle fractional shortening, were significantly improved in the animals transplanted with SMSCs mixed with the nanofiber scaffolds (59.31 ± 4.9% and 31.91 ± 8.1%), compared to those with SMSCs alone (48.31 ± 9.2% and 23.58 ± 8.5%). In conclusion, transplantation of SMSCs mixed with the self-assembling polypeptide RAD16-II is more effective to promote myocardial regeneration and attenuate cardiac injury in a rat model of myocardial infarction. [ABSTRACT FROM AUTHOR]

Polymeric nanofibers fabricated via electrospinning are regarded as promising scaffolds for biomimicking a native extracellular matrix. However, electrospun scaffolds have poor porosity, resulting in cells being unable to infiltrate into the scaffolds but grow only on its surface. In this study, we modified regular electrospinning into rotating multichannel electrospinning (RM-ELSP) to produce microparticles and nanofibers simultaneously. Gelatin nanofibers (0.1–1 μm) and polycaprolactone (PCL) microparticles (0.5–10 μm) were formed and well-mixed. Adjusting the concentration of PCL and/or gelatin, we can fabricate various microparticles/nanofibers composites with different sizes of PCL particles and different diameters of gelatin nanofibers depending on their concentrations (2–10%) during electrospinning. Using PCL particles as a pore generator, we obtained gelatin nanofiber scaffolds with controllable pore size and porosity. Cells adhere and grow into the scaffold easily during in vitro cell culture. [ABSTRACT FROM AUTHOR]

Tissue engineering of implantable cellular constructs is an emerging cellular therapy for hepatic disease. In this study, we tested the ability of poly(ε-caprolactone) (PCL) nanofiber scaffold to support and maintain hepatic differentiation of human cord blood-derived unrestricted somatic stem cells (USSCs) in vitro. USSCs, self-renewing pluripotent cells, were isolated from human cord blood. The electrospun PCL nanofiber porous scaffold was constructed of uniform, randomly oriented nanofibers. USSCs were seeded onto PCL nanofiber scaffolds, and were induced to differentiate into hepatogenic lineages by culturing with differentiation factors for 6 weeks. RT-PCR analysis of endoderm and hepatic-specific gene expression, immunohistochemical detection of cytokeratin 18 (CK-18), α-fetoprotein, albumin, glycogen storage and indocyanine green uptake confirmed the differentiation of USSCs into endoderm and hepatocyte-like cells. In the present study, we show that hepatocyte-like cells differentiated from USSCs on the PCL nanofiber scaffold can be candidate for tissue engineering and cell therapy of hepatic tissues. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

To enhance cell attachment and promote liver functions of hepatocytes cultured in bioreactors, a chitosan nanofiber scaffold was designed and prepared via electrospinning. Effects of the scaffold on hepatocyte adhesion, viability and function were then investigated. Data showed that hepatocytes on chitosan nanofiber scaffold exhibited better viability and tighter cell-substrate contact than cells on regular chitosan film. In addition, urea synthesis, albumin secretion and cytochrome P450 activity of hepatocytes on chitosan nanofiber scaffold were all 1.5 to 2 folds higher than the controls. Glycogen synthesis was also increased as compared with the controls. These results suggested the potential application of this chitosan nanofiber scaffold as a suitable substratum for hepatocyte culturing in bioreactors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The graphene oxide and polycaprolactone composite scaffolds were fabricated successfully by electrospinning method. • The presence of GO in PCL scaffold increases an effect on cell attachment, proliferation, infiltration into the scaffold, and neuronal differentiation. • Epidural adipose tissue derived MSC has high neural differentiation capacity in graphene oxide and polycaprolactone scaffold. Stem cell destiny can be controlled with scaffold biomaterials in tissue engineering and regenerative medicine. This study aimed to investigate the neuronal differentiation potential of human adipose tissue-derived mesenchymal stem cells in graphene nanofiber matrix in vitro. Stem cell isolation was performed from adipose tissue taken from human by mechanical and enzymatic methods. The differentiation potential was examined after incubation of adipose stem cells in normal medium and neural differentiation medium, on graphene oxide (GO) and polycaprolactone (PCL) composite scaffolds produced by electrospinning technique. In vitro studies indicated that the presence of GO in PCL scaffold increases an effect on cell attachment, proliferation, infiltration into the scaffold, and neuronal differentiation. Also, unlike subcutaneous tissue, it has been shown immunohistochemically that mesenchymal stem cells derived from epidural adipose tissue tend to differentiate into oligodendrocytes. [ABSTRACT FROM AUTHOR]

Abstract: Development of new materials for tissue engineering can be facilitated by the capacity to efficiently monitor in vivo the survival, proliferation and differentiation behaviour of cells implanted in different target tissues. We present here the application of a previously developed platform that allows to monitor in real time the survival and proliferative behaviour of implanted cells in two anatomical sites: subcutaneous and intramuscular. Basically, the system is based on the use of a non-invasive bioluminescence imaging (BLI) technique to detect luciferase expressing C57BL/6 cells, mouse embryonic fibroblasts, seeded in two sets of scaffolds: 1, a RAD16-I self-assembling peptide nanofiber matrix and 2, a composite consisted of the same RAD16-I nanofibers contained into a microporous biorubber scaffold. Interestingly, our results indicated considerable differences in the behaviour of implanted cells in each scaffold type. We observed that the self-assembling peptide scaffold alone foster cell survival and promotes cell proliferation where the composite scaffold not. Since self-assembling peptide scaffolds presents value stiffness proximal to the implanted tissues it is suggestive to think that harder materials will provide a physical constriction for cells to proliferate as well as mechanical discontinuity. We therefore propose that it is important to close match the implantation environment with the cell/material constructs in order to obtain the best response of the cells, illustrating the convenience of this strategy for the development of new tissue engineering platforms. [Copyright &y& Elsevier]

Abstract: In traumatic spinal cord injury, loss of neurological function is due to the inability of damaged axons to regenerate across large, cystic cavities. It has recently been demonstrated that a self-assembled nanofiber scaffold (SAPNS) could repair the injured optical pathway and restore visual function. To demonstrate the possibility of using it to repair spinal cord injury, transplanted neural progenitor cells and Schwann cells were isolated from green fluorescent protein–transgenic rats, cultured within SAPNS, and then transplanted into the transected dorsal column of spinal cord of rats. Here we report the use of SAPNS to bridge the injured spinal cord of rats, demonstrating robust migration of host cells, growth of blood vessels, and axons into the scaffolds, indicating that SAPNS provides a true three-dimensional environment for the migration of living cells. [Copyright &y& Elsevier]

We investigated the potential of a nanofiber-based poly(DL-lactide-co-glycolide) (PLGA) scaffold to be used for cartilage reconstruction. The mechanical properties of the nanofiber scaffold, degradation of the scaffold and cellular responses to the scaffold under mechanical stimulation were studied. Three different types of scaffold (lactic acid/glycolic acid content ratio = 75 : 25, 50 : 50, or a blend of 75 : 25 and 50 : 50) were tested. The tensile modulus, ultimate tensile stress and corresponding strain of the scaffolds were similar to those of skin and were slightly lower than those of human cartilage. This suggested that the nanofiber scaffold was sufficiently mechanically stable to withstand implantation and to support regenerated cartilage. The 50 : 50 PLGA scaffold was degraded faster than 75 : 25 PLGA, probably due to the higher hydrophilic glycolic acid content in the former. The nanofiber scaffold was degraded faster than a block-type scaffold that had a similar molecular weight. Therefore, degradation of the scaffold depended on the lactic acid/glycolic acid content ratio and might be controlled by mixing ratio of blend PLGA. Cellular responses were evaluated by examining toxicity, cell proliferation and extracellular matrix (ECM) formation using freshly isolated chondrocytes from porcine articular cartilage. The scaffolds were non-toxic, and cell proliferation and ECM formation in nanofiber scaffolds were superior to those in membrane-type scaffolds. Intermittent hydrostatic pressure applied to cell-seeded nanofiber scaffolds increased chondrocyte proliferation and ECM formation. In conclusion, our nanofiber-based PLGA scaffold has the potential to be used for cartilage reconstruction. [ABSTRACT FROM AUTHOR]

Abstract: Primary rat hepatocytes self-assemble into multi-cellular spheroids and maintain differentiated functions when cultured on a two-dimensional (2-D) substrate conjugated with galactose ligand. The aim of this study is to investigate how a functional nanofiber scaffold with surface-galactose ligand influences the attachment, spheroid formation and functional maintenance of rat hepatocytes in culture, as compared with the functional 2-D substrate. Highly porous nanofiber scaffolds comprising of fibers with an average diameter of 760nm were prepared by electrospinning of poly(&z.epsiv;-caprolactone-co-ethyl ethylene phosphate) (PCLEEP), a novel biodegradable copolymer. Galactose ligand with a density of 66nmol/cm2 was achieved on the nanofiber scaffold via covalent conjugation to a poly(acrylic acid) spacer UV-grafted onto the fiber surface. Hepatocytes cultured on the galactosylated PCLEEP nanofiber scaffold exhibited similar functional profiles in terms of cell attachment, ammonia metabolism, albumin secretion and cytochrome P450 enzymatic activity as those on the functional 2-D substrate, although their morphologies are different. Hepatocytes cultured on galactosylated PCLEEP film formed 50–300μm spheroids that easily detached from surface upon agitation, whereas hepatocytes cultured on galactosylated nanofiber scaffold formed smaller aggregates of 20–100μm that engulfed the functional nanofibers, resulting in an integrated spheroid-nanofiber construct. [Copyright &y& Elsevier]