Aligned Scaffolds Research Articles

Compatibility and function of human induced pluripotent stem cell derived cardiomyocytes on an electrospun nanofibrous scaffold, generated from an ionomeric polyurethane composite.

Synthetic scaffolds are needed for generating organized neo-myocardium constructs to promote functional tissue repair. This study investigated the biocompatibility of an elastomeric electrospun degradable polar/hydrophobic/ionic polyurethane (D-PHI) composite scaffold with human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). The composite material was electrospun to generate scaffolds, with nanofibres oriented in aligned or random directions. These features enabled the authors to evaluate the effect of characteristic elements which mimic that of the native extracellular matrix (alignment, chemical heterogeneity, and fiber topography) on hiPSC-CMs activity. The functional nature of the hiPSC-CM cultured on gelatin and Matrigel-coated scaffolds were assessed, investigating the influence of protein interactions with the synthetic substrate on subsequent cell phenotype. After 7 days of culture, high hiPSC-CM viability was observed on the scaffolds. The cells on the aligned scaffold were elongated and demonstrated aligned sarcomeres that oriented parallel to the direction of the fibers, while the cells on random scaffolds and a tissue culture polystyrene (TCPS) control did not exhibit such an organized morphology. The hiPSC-CMs cultured on the scaffolds and TCPS expressed similar levels of cardiac troponin-T, but there was a higher expression of ventricular myosin light chain-2 on the D-PHI composite scaffolds versus TCPS, indicating a higher proportion of hiPSC-CM exhibiting a ventricular cardiomyocyte like phenotype. Within 7 days, the hiPSC-CMs on aligned scaffolds and TCPS beat synchronously and had similar conductive velocities. These preliminary results show that aligned D-PHI elastomeric scaffolds allow hiPSC-CMs to demonstrate important cardiomyocytes characteristics, critical to enabling their future potential use for cardiac tissue regeneration.

Modulated plasmonic nanofibrous scaffold reinforced breast cancer photo-ablation and breast neurotization with resensation

Herein, we report the bioactivity of the hybrid plasmonic aligned nanofibrous scaffolds composed of reduced graphene oxide (rGO, 209 nm) nanosheets enfolded gold nanorods (AuNR) with polycaprolactone (PCL) for breast cancer photo-therapy and subsequent nerve regeneration. The strategic inclusion of 0.00068 wt% (OD = 4.0) of monodispersed AuNR-rGO in PCL (AuNR-rGO@PCL (4.0)) leads to significant higher physicochemical and optical properties such as higher mechanical strength (7-fold increase), electrical conductivity (∼6-times enhancement), larger surface area (6.4 times), and more NIR light absorbance. Hence, the AuNR-rGO@PCL (4.0) was found to be an excellent photo agent for breast tumor ablation with more than 90% cancer cell (MCF-7) death under 808 nm NIR irradiation at low laser power density (0.72 W/cm2). Also, the nanofibrous scaffold was observed to have a substantial effect on adhesion, proliferation, growth, and differentiation of PC12 and high affinity to S42 cell proliferation and migration which led to an exceptional nerve growth with a 2.5-fold (with NIR light after 3 days) and 2-fold (without NIR light after 7 days) increase in neurite length in comparison to PCL. The present study provides a new bioactive, biocompatible, non-toxic, and bifunctional aligned plasmonic scaffolds as an excellent single platform for breast cancer treatment and potential bioimplant to regain sensation loss after breast surgery and reconstruction.

Thermal conductivity and compressive strength of silicone rubber composites enhanced by aligned carbon nanofiber scaffold

AbstractPolymer composites with high enough thermal conductivity, known as thermal interface materials (TIMs), are continuously pursued in the thermal management of high‐power density electronic and energy devices. In this article, to improve the heat transfer performance of TIMs, we constructed an aligned carbon nanofiber (CNFs) scaffold via the freeze‐casting method to serve as heat conduction paths in the TIMs. The composites of aligned CNF scaffold and silicone rubber were obtained by immersing the aligned scaffold into the silicone rubber with vacuum assist. We studied the influences of different CNFs diameters on the thermal conductivity of the composites, the pore sizes of the aligned CNF scaffold and the thermal conductivity of the composites fabricated under different freezing temperatures, and also the mechanical properties of the composites. Owing to the aligned scaffold, providing directional and continuous heat conduction paths, the thermal conductivity of the composites reached 3.17 W/(m·K) at 7.73 vol% CNFs. Additionally, the compressive strength and fracture strain of the composites were also greatly improved.

Controlling scaffold conductivity and pore size to direct myogenic cell alignment and differentiation.

Skeletal muscle's combination of three‐dimensional (3D) anisotropy and electrical excitability is critical for enabling normal movement. We previously developed a 3D aligned collagen scaffold incorporating conductive polypyrrole (PPy) particles to recapitulate these key muscle properties and showed that the scaffold facilitated enhanced myotube maturation compared with nonconductive controls. To further optimize this scaffold design, this work assessed the influence of conductive polymer incorporation and scaffold pore architecture on myogenic cell behavior. Conductive PPy and poly(3,4‐ethylenedioxythiophene) (PEDOT) particles were synthesized and mixed into a suspension of type I collagen and chondroitin sulfate prior to directional freeze‐drying to produce anisotropic scaffolds. Energy dispersive spectroscopy revealed homogenous distribution of conductive PEDOT particles throughout the scaffolds that resulted in a threefold increase in electrical conductivity while supporting similar myoblast metabolic activity compared to nonconductive scaffolds. Control of freezing temperature enabled fabrication of PEDOT‐doped scaffolds with a range of pore diameters from 98 to 238 μm. Myoblasts conformed to the anisotropic contact guidance cues independent of pore size to display longitudinal cytoskeletal alignment. The increased specific surface area of the smaller pore scaffolds helped rescue the initial decrease in myoblast metabolic activity observed in larger pore conductive scaffolds while also promoting modestly increased expression levels of the myogenic marker myosin heavy chain (MHC) and gene expression of myoblast determination protein (MyoD). However, cell infiltration to the center of the scaffolds was marginally reduced compared with larger pore variants. Together these data underscore the potential of aligned and PEDOT‐doped collagen scaffolds for promoting myogenic cell organization and differentiation.

Fibroblast cell responses to physical cues of the triangular prism micropattern and aligned nanofibrous scaffold for promoting wound closure

Cells are sensitive to the microenvironment and multiscale surface topographies were crucial for modulating cell activities and promoting the wound healing process. Herein, we fabricated an engineered microstructural topography surface on the nanofibre scaffold as mimicking a cellular microenvironment. The scaffold consisted of nanofibre matrices arranged in a triangular prism micropattern with either aligned or random nanofibres. The morphological analysis revealed that the scaffolds had a compact layer of nanofibres, and the peak of the triangular prism was present after separation. The in-vitro analysis presents that the human dermal fibroblast cells (HDF) are distributed homogenously and aligned along the structural scaffold. The triangular prism micropattern supported cell movement, resulting in improved cell elongation behavior. In in-vivo analysis, the aligned microstructural scaffold demonstrated a better therapeutic effect and advanced epithelialization on day 7. The length of the epidermis tongue of the aligned and random microstructural scaffold was 1983 ± 132.94 µm and 1638.04 ± 115.85 µm, respectively. By day 14, the aligned microstructural scaffold had enhanced the wound healing process by decreasing the wound area and had achieved a 97% wound closure. This indicated that the aligned microstructural scaffold was able to guide the cell movement required for wound healing application.

Evaluation of osteogenic differentiation of human mesenchymal stem cells (hMSCs) on random and aligned polycaprolactone-polyaniline-gelatin scaffolds.

Introduction: Biocompatible and biodegradable scaffolds have gained tremendous attention because of their potential in tissue engineering. In this study, the aim was to reach a feasible setup from a ternary hybrid of polyaniline (PANI), gelatin (GEL), and polycaprolactone (PCL) to fabricate aligned and random nanofibrous scaffolds by electrospinning for tissue engineering purposes. Methods: Different setups of PANI, PCL, and GEL were electrospun. Then, the best aligned and random scaffolds were chosen. SEM imaging was done to observe nanoscaffolds before and after stem cell differentiation. Mechanical properties of the fibers were tested. Their hydrophilicity was measured using the sessile drop method. SNL Cells were then seeded onto the fiber, and MTT was performed to assess its toxicity. The cells were then differentiated. After osteogenic differentiation, alkaline phosphatase activity, calcium content assay, and alizarin red staining were done to check the validity of osteogenic differentiation. Results: The two chosen scaffolds had an average diameter of 300 ± 50 (random) and 200 ± 50 (aligned). MTT was performed and its results showed that the scaffolds were non-toxic to cells. After stem cell differentiation, alkaline phosphatase activity was performed, confirming differentiation on both types of scaffolds. Calcium content and alizarin red staining also confirmed stem cell differentiation. Morphological analysis showed no difference regarding differentiation on either type of scaffold. However, unlike on the random fibers, cells followed a specific direction and had a parallel-like growth pattern on aligned fibers. Conclusion: All in all, PCL-PANI-GEL fibers showed to be capable candidates for cell attachment and growth. Furthermore, they proved to be of excellent use in bone tissue differentiation.

Mesenchymal stem cell culture in aligned porous hydroxyapatite scaffolds using a multiwell plate bioreactor for bone tissue engineering

Regeneration of bone lost by trauma, diseases and aging, and restoration of its load-bearing function are major clinical challenges. Hydroxyapatite (HA) is a clinically proven scaffold material for bone grafting, but the random-pore structure limits the homing of the cells inside the graft and the bone regeneration progresses with the resorption of the graft material. This work is based on the hypothesis that aligned through pores in the graft will lead to a faster healing by homing the local cells inside and provide a better environment for new bone formation through the graft structure. The investigation was done using aligned porous HA scaffolds seeded with human Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs) and cultured in a multiwell format bioreactor setup. The cell adhesion was studied by microscopy, cell proliferation was evaluated by Alamar blue assay and osteogenic differentiation was confirmed by biochemical and molecular assays. The results indicate that the hWJ-MSCs infiltrated through the aligned porous network of the scaffold, proliferated well when cultured in the expansion medium, and differentiated into osteogenic lineage when cultured in the differentiation medium.

Abstract 548: Prolonging The Viability Of Induced Pluripotent Stem Cell-derived Endothelial Cells For Treatment Of Peripheral Arterial Disease Using Engineered Biomaterials

Dysfunctional endothelial cells (EC) can restrict flow in the extremities, leading to limb ischemia. We aim to improving revascularization of ischemic limbs using cell therapy, augmented with spatially patterned scaffolds that promote survival. The purpose was to evaluate the effect spatially patterned scaffolds on endothelial cell survival. The biophysical parameters of collagen scaffolds (alignment, crosslinking, and fibril diameter) were characterized with atomic force microscopy and degradation assays. Cytoskeletal arrangement of primary human coronary artery ECs and human induced pluripotent stem cell (iPSC)-derived ECs on collagen scaffolds was evaluated by F-actin staining. To evaluate the effect of mechanical properties on cell viability in vitro, Live/Dead and MTS assays were used. Cell seeded scaffolds were implanted into a mouse hindlimb ischemia model, and cell survival was tracked by bioluminescent imaging. Both primary EC and iPSC-ECs reorganized their F-actin cytoskeleton corresponding to the alignment of the fibrils, irrespective of crosslinking degree, stiffness or fibril diameter. When cells were grown in hypoxic mimicking ischemia however, viability was improved using aligned scaffolds with 200 nm fibril diameter. Degradation assays showed that scaffolds with higher crosslinking had significantly more durability. When cell-seeded scaffolds were implanted to the ischemic limb, the aligned scaffolds with 200nm fibril diameter had the highest survival, confirming in vitro studies. Aligned collagen scaffolds with 200nm fibril diameter and high cross-linking degree led to improved viability of primary and iPSC-ECs in a mouse model of PAD.

3D porous scaffolds from wheat glutenin for cultured meat applications

Scaffolds suitable for use in food products are crucial components for the production of cultured meat. Here, wheat glutenin, an inexpensive and abundant plant-based protein, was used to develop 3D porous scaffolds for cultured meat applications. A physical cross-linking method based on water annealing was developed for the fabrication of porous glutenin sponges and fibrous aligned scaffolds. The pore sizes ranged from 50 to 250 μm, with compressive modulus ranges from 0.5 to 1.9 kPa, depending on the percentage of glutenin (2%–5%) used in the process. The sponges were stable in PBS with refrigeration for at least six months after water annealing. The glutenin scaffolds supported the proliferation and differentiation of C2C12 mouse skeletal myoblasts and bovine satellite cells (BSCs) without the need to add specific cell adhesive proteins or other coatings. The low cost and food safe production process avoided the use of toxic cross-linkers and animal-derived extracellular matrix (ECM) coatings, suggesting that this as approach is a promising system for scaffolds useful in cultivated meat applications.

Tissue-specific melt electrowritten polymeric scaffolds for coordinated regeneration of soft and hard periodontal tissues.

Periodontitis is a chronic inflammatory condition that often causes serious damage to tooth-supporting tissues. The limited successful outcomes of clinically available approaches underscore the need for therapeutics that cannot only provide structural guidance to cells but can also modulate the local immune response. Here, three-dimensional melt electrowritten (i.e., poly(ε-caprolactone)) scaffolds with tissue-specific attributes were engineered to guide differentiation of human-derived periodontal ligament stem cells (hPDLSCs) and mediate macrophage polarization. The investigated tissue-specific scaffold attributes comprised fiber morphology (aligned vs. random) and highly-ordered architectures with distinct strand spacings (small 250 μm and large 500 μm). Macrophages exhibited an elongated morphology in aligned and highly-ordered scaffolds, while maintaining their round-shape on randomly-oriented fibrous scaffolds. Expressions of periostin and IL-10 were more pronounced on the aligned and highly-ordered scaffolds. While hPDLSCs on the scaffolds with 500 μm strand spacing show higher expression of osteogenic marker (Runx2) over 21 days, cells on randomly-oriented fibrous scaffolds showed upregulation of M1 markers. In an orthotopic mandibular fenestration defect model, findings revealed that the tissue-specific scaffolds (i.e., aligned fibers for periodontal ligament and highly-ordered 500 μm strand spacing fluorinated calcium phosphate [F/CaP]-coated fibers for bone) could enhance the mimicking of regeneration of natural periodontal tissues.

Polydopamine-coated polycaprolactone/carbon nanotube fibrous scaffolds loaded with brain-derived neurotrophic factor for peripheral nerve regeneration

Carbon nanotubes (CNTs) have attracted increasing attention in the field of peripheral nerve tissue engineering due to their unique structural and physical characteristics. In this study, a novel type of aligned conductive scaffolds composed of polycaprolactone (PCL) and CNTs were fabricated via electrospinning. Utilizing mussel-inspired polydopamine (PDA) surface modification, brain-derived neurotrophic factor (BDNF) was loaded onto PCL/CNT fibrous scaffolds to obtain PCL/CNT-PDA-BDNF fibrous scaffolds capable of the sustained release of BDNF over 28 d. Schwann cells were cultured on these scaffolds, and the effect of the scaffolds on peripheral nerve regeneration in vitro was assessed by studying cell proliferation, morphology and the expressions of myelination-related genes S100, P0 and myelin basic protein. Furthermore, the effect of these scaffolds on peripheral nerve regeneration in vivo was investigated using a 10 mm rat sciatic nerve defect model. Both the in vitro and in vivo results indicate that PCL/CNT-PDA-BDNF fibrous scaffolds effectively promote sciatic nerve regeneration and functional recovery. Therefore, PCL/CNT-PDA-BDNF fibrous scaffolds have great potential for peripheral nerve restoration.

Design of ECM Functionalized Polycaprolactone Aligned Nanofibers for Peripheral Nerve Tissue Engineering

PurposePeripheral nerve injury (PNI) and its regeneration continue to remain a significant medical burden worldwide. The current treatment strategies used to treat PNI are often associated with multiple complications and yet do not achieve complete motor and sensory functions. Recently, synthetic biodegradable nerve conduits have become one the most commonly used conduits to repair small gaps in nerve injury. But they have not shown better results than nerve grafts possibly because of the lack of biological microenvironment required for axonal growth. Schwann cells play a very crucial role in peripheral nerve regeneration where activated SCs produce multiple neurotrophic factors that help in remyelination and immune modulation during nerve repair. Studies have shown that nanofibrous scaffolds have better bioactivity and more closely mimic the native structure of the extracellular matrix. Therefore, the present study was focused on designing a nanofibrous scaffold that would cover the roles of both structural support for the cells that can provide a microenvironment with biological cues for nerve growth and regeneration.MethodsDecellularized Schwann cell ECM were spin-coated on polycaprolactone random and aligned nanofibrous scaffolds and their compatibility was evaluated using Schwann cells.ResultsSchwann cells displayed growth in the direction of the aligned PCL nanofibers and ACM treated exhibited appropriate bipolar morphology indicating that these modified fibers could provide directional cues making them highly suitable for neuronal cell growth.ConclusionOur results indicate that the fabricated aligned SC-ACM treated PCL scaffolds would be a potential biomaterial to treat peripheral nerve injuries and promote regeneration.Graphical

An Ultrastrong and Antibacterial Silver Nanowire/Aligned Cellulose Scaffold Composite Film for Electromagnetic Interference Shielding.

Constructing multifunctional electromagnetic interference (EMI) shielding films with superior mechanical strength has sparked a lot of interest in the fields of wearable electronics. In this work, the conductive silver nanowires (AgNWs) were synthesized and impregnated into the highly aligned cellulose scaffold (CS) fabricated by wood delignification followed by hot-pressing and polydimethylsiloxane (PDMS) dipping processes to obtain the outstanding EMI shielding cellulosic film (d-AgNWs@CS-PDMS). The consecutively conductive pathway of AgNWs was constructed in the microchannels of the CS as a result of the hydrogen bonding between AgNWs and cellulose fibers, which is conducive to the reflection of incident EM waves. The higher degree of nanofiber alignment and the compact conductive network were improved by densification upon hot pressing, which endows the composite film with striking mechanical properties (maximum tensile strength of 511.8 MPa) and superb EMI shielding performance (shielding effectiveness value of 46 dB with a filler content of 21.6 wt %) at the X band (8.2-12.4 GHz). Moreover, the existence of an intensive AgNWs network and the introduction of the PDMS layer improve the hydrophobicity and antibacterial activity of the composite film, avoiding serious health concerns in the long-term wearing. These results demonstrate that the obtained d-AgNWs@CS-PDMS composite film has high potential as an EMI shielding material used for wearable devices.

Regulation of Schwann Cell and DRG Neurite Behaviors within Decellularized Peripheral Nerve Matrix.

Decellularized nerve hydrogels (dNHs) containing bioactive molecules are promising biomaterials for peripheral nerve injury (PNI) treatment and have been extensively applied in clinical and preclinical practice. However, most previous research projects studied their influences on nerve-related cellular behaviors in two dimensions (2D) without taking hydrogel biomechanics into consideration. The molecular mechanisms underlying the beneficial microenvironment provided by dNHs also remain unclear. In this study, dNHs from rat sciatic nerves were prepared, and their effects on Schwann cell (SC) and dorsal root ganglion (DRG) neurite behaviors were evaluated and compared to commercial rat tail type I collagen (Col) hydrogels in three-dimensional (3D) environments. We found that dNHs could promote SC proliferation and neurite outgrowth, and both the hydrogel mechanics and components contributed to the dNH functionalization. Through proteomics analysis, we found that laminin (LAM) and type V collagen (COLV) exclusively and abundantly existed in dNHs. By adding exogenous LAM and COLV into Col hydrogels, we demonstrated that they regulated SC gene expression and that LAM could promote SC spreading and neurite outgrowth, while COLV improved SC proliferation. Lastly, dNHs were fabricated into paper-like, aligned nerve scaffolds through unidirectional freezing to expand the dNH applications in PNI treatment.

Silk-inspired fiber implant with multi-cues enhanced bionic microenvironment for promoting peripheral nerve repair

Successful repair and desirable functional recovery of large-gap nerve injuries using artificial nerve implants remains a significant clinical challenge. The beneficial bionic microenvironment within scaffolds can significantly promote the outgrowth of newborn nerve tissues after implantation. Herein, we developed an aligned silk-inspired fiber scaffold (RGD@ASFFs) with a synergistic effect of an extracellular matrix mimicking physical cues and RGD (Arg-Gly-Asp) signals to provide an enhanced cell-friendly microenvironment for repairing large-gap peripheral nerve injuries. The topographic alignment of the methacrylated silk fibroin electrospun fibers effectively facilitated axonal guidance and oriented Schwann cell growth. Importantly, the mechanical cue combined with cell adhesion signals provided by RGD peptides further triggered enriched myelination of Schwann cells by nuclear translocation of Yes-associated protein 1 (YAP) to secrete neurotrophins to support axonal growth. Moreover, benefiting from improved neuronal extension and re-myelination, promising motor function recovery in vivo was achieved by RGD@ASFFs, which is comparable to that of autografts. Thus, the design of this engineered bionic scaffold is a powerful strategy for peripheral nerve defect repair.

Fibrous Scaffolds for Muscle Tissue Engineering Based on Touch-Spun Poly(Ester-Urethane) Elastomer.

Development of fiber-spinning technologies and materials with proper mechanical properties is highly important for the manufacturing of aligned fibrous scaffolds mimicking structure of the muscle tissues. Here, the authors report touch spinning of a thermoplastic poly(1,4-butylene adipate)-based polyurethane elastomer, obtained via solvent-free polymerization. This polymer possesses a combination of important advantages such as 1) low elastic modulus in the range of a few MPa, 2) good recovery ratio and 3) resilience, 4) processability, 5) nontoxicity, 6) biocompatibility, and 7) biodegradability that makes it suitable for fabrication of structures mimicking extracellular matrix of muscle tissue. Touch spinning allows fast and precise deposition of highly aligned micro- and nano-fibers without use of high voltage. C2C12myoblasts readily align along soft polymer fibers and demonstrate high viability as well as proliferation that make proposed combination of polymer and fabrication method highly suitable for engineering skeletal muscles.

Spontaneous Formation of 3D Breast Cancer Tissues on Electrospun Chitosan/Poly(ethylene oxide) Nanofibrous Scaffolds.

Three-dimensional (3D) tissue culture has attracted a great deal of attention as a result of the need to replace the conventional two-dimensional cell cultures with more meaningful methods, especially for understanding the sophisticated nature of native tumor microenvironments. However, most techniques for 3D tissue culture are laborious, expensive, and limited to spheroid formation. In this study, a low-cost and highly effective nanofibrous scaffold is presented for spontaneous formation of reproducible 3D breast cancer microtissues. Experimentally, aligned and non-aligned chitosan/poly(ethylene oxide) nanofibrous scaffolds were prepared at one of two chitosan concentrations (2 and 4 wt %) and various electrospinning parameters. The resulting fabricated scaffolds (C2P1 and C4P1) were structurally and morphologically characterized, as well as analyzed in silico. The obtained data suggest that the fiber diameter, surface roughness, and scaffold wettability are tunable and can be influenced based on the chitosan concentration, electrospinning conditions, and alignment mode. To test the usefulness of the fabricated scaffolds for 3D cell culture, a breast cancer cell line (MCF-7) was cultured on their surfaces and evaluated morphologically and biochemically. The obtained data showed a higher proliferation rate for cells grown on scaffolds compared to cells grown on two-dimensional adherent plates (tissue culture plate). The MTT assay revealed that the rate of cell proliferation on nanofibrous scaffolds is statistically significantly higher compared to tissue culture plate (P ≤ 0.001) after 14 days of culture. The formation of spheroids within the first few days of culture shows that the scaffolds effectively support 3D tissue culture from the outset of the experiment. Furthermore, 3D breast cancer tissues were spontaneously formed within 10 days of culture on aligned and non-aligned nanofibrous scaffolds, which suggests that the scaffolds imitate the in vivo extracellular matrix in the tumor microenvironment. Detailed mechanisms for the spontaneous formation of the 3D microtissues have been proposed. Our results suggest that scaffold surface topography significantly influences tissue formation and behavior of the cells.

Structural alignment guides oriented migration and differentiation of endogenous neural stem cells for neurogenesis in brain injury treatment

Radial glia (RG) cells that align in parallel in the embryonic brain are found to be able to guide the directed migration of neurons in response to brain injury. Therefore, biomaterials with aligned architectures are supposed to have positive effects on neural migration and neurogenic differentiation for brain injury repair that are rarely addressed, although they have been widely demonstrated in spinal cord and peripheral nerve system. Here, we present a highly biomimetic scaffold of aligned fibrin hydrogel (AFG) that mimics the oriented structure of RG fibers. Through a combination of histological, behavioral, imaging, and transcriptomic analyses, we demonstrated that transplanting the AFG scaffold into injured cortical brains promotes effective migration, differentiation, and maturation of endogenous neural stem cells, resulting in neurological functional recovery. Therefore, this study will light up a new perspective on applying an aligned scaffold to promote cortical regeneration after injury by inducing endogenous neurogenesis.

The application of human periodontal ligament stem cells and biomimetic silk scaffold for in situ tendon regeneration

BackgroundWith the development of tissue engineering, enhanced tendon regeneration could be achieved by exploiting suitable cell types and biomaterials. The accessibility, robust cell amplification ability, superior tendon differentiation potential, and immunomodulatory effects of human periodontal ligament stem cells (hPDLSCs) indicate their potential as ideal seed cells for tendon tissue engineering. Nevertheless, there are currently no reports of using PDLSCs as seed cells. Previous studies have confirmed the potential of silk scaffold for tendon tissue engineering. However, the biomimetic silk scaffold with tendon extracellular matrix (ECM)-like structure has not been systematically studied for in situ tendon regeneration. Therefore, this study aims to evaluate the effects of hPDLSCs and biomimetic silk scaffold on in situ tendon regeneration.MethodsHuman PDLSCs were isolated from extracted wisdom teeth. The differentiation potential of hPDLSCs towards osteo-, chondro-, and adipo-lineage was examined by cultured in different inducing media. Aligned and random silk scaffolds were fabricated by the controlled directional freezing technique. Scaffolds were characterized including surface structure, water contact angle, swelling ratio, degradation speed and mechanical properties. The biocompatibility of silk scaffolds was evaluated by live/dead staining, SEM observation, cell proliferation determination and immunofluorescent staining of deposited collagen type I. Subsequently, hPDLSCs were seeded on the aligned silk scaffold and transplanted into the ruptured rat Achilles tendon. Scaffolds without cells served as control groups. After 4 weeks, histology evaluation was carried out and macrophage polarization was examined to check the repair effects and immunomodulatory effects.ResultsHuman PDLSCs were successfully isolated, and their multi-differentiation potential was confirmed. Compared with random scaffold, aligned silk scaffold had more elongated and aligned pores and promoted the proliferation and ordered arrangement of hPDLSCs. After implantation into rat Achilles tendon defect, hPDLSCs seeded aligned silk scaffold enhanced tendon repair with more tendon-like tissue formation after 4 weeks, as compared to the scaffold-only groups. Higher expression of CD206 and lower expression of iNOS, IL-1β and TNF-α were found in the hPDLSCs seeded aligned silk scaffold group, which revealed its modulation effect of macrophage polarization from M1 to M2 phenotype.ConclusionsIn summary, this study demonstrates the efficacy of hPDLSCs as seed cells and aligned silk scaffold as a tendon-mimetic scaffold for enhanced tendon tissue engineering, which may have broad implications for future tendon tissue engineering and regenerative medicine researches.

3D culture platform of human iPSCs-derived nociceptors for peripheral nerve modeling and tissue innervation

Functional humanized in vitro nerve models are coveted as an alternative to animal models due to their ease of access, lower cost, clinical relevance and no need for recurrent animal sacrifice. To this end, we developed a sensory nerve model using induced pluripotent stem cells-derived nociceptors that are electrically active and exhibit a functional response to noxious stimuli. The differentiated neurons were co-cultured with primary Schwann cells on an aligned microfibrous scaffold to produce biomimetic peripheral nerve tissue. Compared to glass coverslips, our scaffold enhances tissue development and stabilization. Using this model, we demonstrate that myelin damage can be induced from hyperglycemia exposure (glucose at 45 mM) and mitigated by epalrestat (1 µM) supplementation. Through fibrin embedding of the platform, we were able to create 3D anisotropic myelinated tissue, reaching over 6.5 mm in length. Finally, as a proof-of-concept, we incorporated pancreatic pseudoislets and endometrial organoids into our nerve platform, to demonstrate the potential in generating nociceptor innervation models. In summary, we propose here an improved tool for neurobiology research with potential applications in pathology modeling, drug screening and target tissue innervation.