Bioengineered 3D ovarian model for long-term multiple development of preantral follicle: bridging the gap for poly(ε-caprolactone) (PCL)-based scaffold reproductive applications.

BACKGROUND: Assisted Reproductive Technologies (ARTs) have been validated in human and animal to solve reproductive problems such as infertility, aging, genetic selection/amplification and diseases. The persistent gap in ART biomedical applications lies in recapitulating the early stage of ovarian folliculogenesis, thus providing protocols to drive the large reserve of immature follicles towards the gonadotropin-dependent phase. Tissue engineering is becoming a concrete solution to potentially recapitulate ovarian structure, mostly relying on the use of autologous early follicles on natural or synthetic scaffolds. Based on these premises, the present study has been designed to validate the use of the ovarian bioinspired patterned electrospun fibrous scaffolds fabricated with poly(ε-caprolactone) (PCL) for multiple preantral (PA) follicle development. METHODS: PA follicles isolated from lamb ovaries were cultured on PCL scaffold adopting a validated single-follicle protocol (Ctrl) or simulating a multiple-follicle condition by reproducing an artificial ovary engrafted with 5 or 10 PA (AO5PA and AO10PA). The incubations were protracted for 14 and 18 days before assessing scaffold-based microenvironment suitability to assist in vitro folliculogenesis (ivF) and oogenesis at morphological and functional level. RESULTS: The ivF outcomes demonstrated that PCL-scaffolds generate an appropriate biomimetic ovarian microenvironment supporting the transition of multiple PA follicles towards early antral (EA) stage by supporting follicle growth and steroidogenic activation. PCL-multiple bioengineering ivF (AO10PA) performed in long term generated, in addition, the greatest percentage of highly specialized gametes by enhancing meiotic competence, large chromatin remodeling and parthenogenetic developmental competence. CONCLUSIONS: The study showcased the proof of concept for a next-generation ART use of PCL-patterned scaffold aimed to generate transplantable artificial ovary engrafted with autologous early-stage follicles or to advance ivF technologies holding a 3D bioinspired matrix promoting a physiological long-term multiple PA follicle protocol.

IVM Advances for Early Antral Follicle-Enclosed Oocytes Coupling Reproductive Tissue Engineering to Inductive Influences of Human Chorionic Gonadotropin and Ovarian Surface Epithelium Coculture.

In vitro maturation (IVM) is not a routine assisted reproductive technology (ART) for oocytes collected from early antral (EA) follicles, a large source of potentially available gametes. Despite substantial improvements in IVM in the past decade, the outcomes remain low for EA-derived oocytes due to their reduced developmental competences. To optimize IVM for ovine EA-derived oocytes, a three-dimensional (3D) scaffold-mediated follicle-enclosed oocytes (FEO) system was compared with a validated cumulus-oocyte complex (COC) protocol. Gonadotropin stimulation (eCG and/or hCG) and/or somatic cell coculture (ovarian vs. extraovarian-cell source) were supplied to both systems. The maturation rate and parthenogenetic activation were significantly improved by combining hCG stimulation with ovarian surface epithelium (OSE) cells coculture exclusively on the FEO system. Based on the data, the paracrine factors released specifically from OSE enhanced the hCG-triggering of oocyte maturation mechanisms by acting through the mural compartment (positive effect on FEO and not on COC) by stimulating the EGFR signaling. Overall, the FEO system performed on a developed reproductive scaffold proved feasible and reliable in promoting a synergic cytoplasmatic and nuclear maturation, offering a novel cultural strategy to widen the availability of mature gametes for ART.

Production and characterization of biocompatible nanofibrous scaffolds made ofß-sitosterolloaded polyvinyl alcohol/tragacanth gum composites.

Electrospun polyvinyl alcohol (PVA) and tragacanth gum (TG) were used to develop nanofibrous scaffolds containing poorly water-solubleß-Sitosterol (ß-S). Different concentrations and ratios of the polymeric composite includingß-S (10% w v-1) in PVA (8% w v-1) combined with TG (0.5 and 1% w v-1) were prepared and electrospun. The synthesis method includes four electrospinning parameters of solution concentration, feeding rate, voltage, and distance of the collector to the tip of the needle, which are independently optimized to achieve uniform nanofibers with a desirable mean diameter for cell culture. The collected nanofibers were characterized by SEM, FTIR, and XRD measurements. A contact angle measurement described the hydrophilicity of the scaffold. MTT test was carried out on the obtained nanofibers containing L929 normal fibroblast cells. The mechanical strength, porosity, and deterioration of the scaffolds were well discussed. The mean nanofiber diameters ranged from 63 ± 20 nm to 97 ± 46 nm. The nanofibers loaded withß-S were freely soluble in water and displayed a remarkable biocompatible nature. The cultured cells illustrated sheet-like stretched growth morphology and penetrated the nanofibrous pores of the PVA/ß-S/TG scaffolds. The dissolution was related to submicron-level recrystallization ofß-S with sufficient conditions for culturing L929 cells. It was concluded that electrospinning is a promising technique for poorly water-solubleß-S formulations that could be used in biomedical applications.

Labeling of endothelial cells with magnetic microbeads by angiophagy.

OBJECTIVES: Attachment of magnetic particles to cells is needed for a variety of applications but is not always possible or efficient. Simpler and more convenient methods are thus desirable. In this study, we tested the hypothesis that endothelial cells (EC) can be loaded with micron-size magnetic beads by the phagocytosis-like mechanism 'angiophagy'. To this end, human umbilical vein EC (HUVEC) were incubated with magnetic beads conjugated or not (control) with an anti-VEGF receptor 2 antibody, either in suspension, or in culture followed by re-suspension using trypsinization. RESULTS: In all conditions tested, HUVEC incubation with beads induced their uptake by angiophagy, which was confirmed by (i) increased cell granularity assessed by flow cytometry, and (ii) the presence of an F-actin rich layer around many of the intracellular beads, visualized by confocal microscopy. For confluent cultures, the average number of beads per cell was 4.4 and 4.2, with and without the presence of the anti-VEGFR2 antibody, respectively. However, while the actively dividing cells took up 2.9 unconjugated beads on average, this number increased to 5.2 if binding was mediated by the antibody. Magnetic pulldown increased the cell density of beads-loaded cells in porous electrospun poly-capro-lactone scaffolds by a factor of 4.5 after 5 min, as compared to gravitational settling (p < 0.0001). CONCLUSION: We demonstrated that EC can be readily loaded by angiophagy with micron-sized beads while attached in monolayer culture, then dispersed in single-cell suspensions for pulldown in porous scaffolds and for other applications.

The Chemotherapeutic Effect of Docetaxel, Cisplatin and Fluorouracil Regimen on Gastric Cancer Stem Cells.

In recent years, chemotherapy targeting cancer stem cells has increasingly garnered interest from the scientists and clinicians. In this study, we explored both in vitro and in vivo if a chemotherapy regimen could arrest gastric tumor growth via demolishing CD24+ and CD44+ cancer stem cells (CSC) in the tumor mass. To facilitate the tumorigenesis in the subcutaneous xenograft model, we employed an electrospun scaffold comprising polydioxanone and gelatin for the delivery of tumor cells. The scaffold sported a highly porous micro-structure and promoted the in vitro and in vivo tumorigenesis without inducing apoptosis. in vivo studies confirmed that the tumor enjoyed an increase of volume by 56.21% and weight by 71.29%, respectively, in a 12-week period. Interestingly, populations of CD24+ and CD44+ cells in the tumor increased by 37% and 274%, respectively. No phenotypic change during tumorigenesis was observed due to the presence of the scaffold. Thereafter, we studied the chemotherapeutic effectiveness of a regimen comprising docetaxel, cisplatin and fluorouracil (DCF) in the scaffold model. The study showed that this regimen demonstrated a strong capability to demolish the CD44+ subpopulation in the tumor. This discovery warrants further study of the DCF regimen for gastric cancer. Moreover, the scaffold offers cancer scientists an accelerated in vivo platform for mechanistic chemotherapy study.

Hierarchically structured nanofibrous scaffolds spatiotemporally mediate the osteoimmune micro-environment and promote osteogenesis for periodontitis-related alveolar bone regeneration.

Periodontitis suffer from inflammation-induced destruction of periodontal tissues, resulting in the serious loss of alveolar bone. Controlling inflammation and promoting bone regeneration are two crucial aspects for periodontitis-related alveolar bone defect treatment. Herein, we developed a hierarchically structured nanofibrous scaffold with a nano-embossed sheath and a bone morphogenetic protein 2-loaded core to match the periodontitis-specific features that spatiotemporally modulated the osteoimmune environment and promoted periodontal bone regeneration. We investigated the potential of this unique scaffold to treat periodontitis-related alveolar bone defects in vivo and in vitro. The results demonstrated that the hierarchically structured scaffold effectively reduced the inflammatory levels in macrophages and enhanced the osteogenic potential of bone mesenchymal stem cells in an inflammatory microenvironment. Moreover, in vivo experiments revealed that the hierarchically structured scaffold significantly ameliorated inflammation in the periodontium and inhibited alveolar bone resorption. Notably, the hierarchically structured scaffold also exhibited a prolonged effect on promoting alveolar bone regeneration. These findings highlight the significant therapeutic potential of hierarchically structured nanofibrous scaffolds for the treatment of periodontitis, and their promising role in the field of periodontal tissue regeneration. STATEMENT OF SIGNIFICANCE: We present a novel hierarchically structured nanofibrous scaffold of coupling topological and biomolecular signals for precise spatiotemporal modulation of the osteoimmune micro-environment. Specifically, the scaffold was engineered via coaxial electrospinning of the poly(ε-caprolactone) sheath and a BMP-2/polyvinyl alcohol core, followed by surface-directed epitaxial crystallization to generate cyclic nano-lamellar embossment on the sheath. With this unique hierarchical structure, the cyclic nano-lamellar sheath provided a direct nano-topographical cue to alleviate the osteoimmune environment, and the stepwise release of BMP-2 from the core provided a biological cue for bone regeneration. This research underscores the potential of hierarchically structured nanofibrous scaffolds as a promising therapeutic approach for periodontal tissue regeneration and highlights their role in advancing periodontal tissue engineering.

Fiber configuration determines foreign body response of electrospun scaffolds:in vitroandin vivoassessments.

Biomaterial scaffolds boost tissue repair and regeneration by providing physical support, delivering biological signals and/or cells, and recruiting endogenous cells to facilitate tissue-material integration and remodeling. Foreign body response (FBR), an innate immune response that occurs immediately after biomaterial implantation, is a critical factor in determining the biological outcomes of biomaterial scaffolds. Electrospinning is of great simplicity and cost-effectiveness to produce nanofiber scaffolds with well-defined physicochemical properties and has been used in a variety of regenerative medicine applications in preclinical trials and clinical practice. A deep understanding of causal factors between material properties and FBR of host tissues is beneficial to the optimal design of electrospun scaffolds with favorable immunomodulatory properties. We herein prepared and characterized three electrospun scaffolds with distinct fiber configurations and investigated their effects on FBR in terms of immune cell-material interactions and host responses. Our results show that electrospun yarn scaffold results in greater cellular immune reactions and elevated FBR inin vivoassessments. Although the yarn scaffold showed aligned fiber bundles, it failed to induce cell elongation of macrophages due to its rough surface and porous grooves between yarns. In contrast, the aligned scaffold showed reduced FBR compared to the yarn scaffold, indicating a smooth surface is also a contributor to the immunomodulatory effects of the aligned scaffold. Our study suggests that balanced porousness and smooth surface of aligned fibers or yarns should be the key design parameters of electrospun scaffolds to modulate host responsein vivo.

Osteogenic Potential and Long-Term Enzymatic Biodegradation of PHB-based Scaffolds with Composite Magnetic Nanofillers in a Magnetic Field.

Millions of people worldwide suffer from musculoskeletal damage, thus using the largest proportion of rehabilitation services. The limited self-regenerative capacity of bone and cartilage tissues necessitates the development of functional biomaterials. Magnetoactive materials are a promising solution due to clinical safety and deep tissue penetration of magnetic fields (MFs) without attenuation and tissue heating. Herein, electrospun microfibrous scaffolds were developed based on piezoelectric poly(3-hydroxybutyrate) (PHB) and composite magnetic nanofillers [magnetite with graphene oxide (GO) or reduced GO]. The scaffolds' morphology, structure, mechanical properties, surface potential, and piezoelectric response were systematically investigated. Furthermore, a complex mechanism of enzymatic biodegradation of these scaffolds is proposed that involves (i) a release of polymer crystallites, (ii) crystallization of the amorphous phase, and (iii) dissolution of the amorphous phase. Incorporation of Fe3O4, Fe3O4-GO, or Fe3O4-rGO accelerated the biodegradation of PHB scaffolds owing to pores on the surface of composite fibers and the enlarged content of polymer amorphous phase in the composite scaffolds. Six-month biodegradation caused a reduction in surface potential (1.5-fold) and in a vertical piezoresponse (3.5-fold) of the Fe3O4-GO scaffold because of a decrease in the PHB ß-phase content. In vitro assays in the absence of an MF showed a significantly more pronounced mesenchymal stem cell proliferation on composite magnetic scaffolds compared to the neat scaffold, whereas in an MF (68 mT, 0.67 Hz), cell proliferation was not statistically significantly different when all the studied scaffolds were compared. The PHB/Fe3O4-GO scaffold was implanted into femur bone defects in rats, resulting in successful bone repair after nonperiodic magnetic stimulation (200 mT, 0.04 Hz) owing to a synergetic influence of increased surface roughness, the presence of hydrophilic groups near the surface, and magnetoelectric and magnetomechanical effects of the material.

Melt Electrowriting Combined with Fused Deposition Modeling Printing for the Fabrication of Three-Dimensional Biomimetic Scaffolds for Osteotendinous Junction Regeneration.

Purpose: This study aims to explore a novel scaffold for osteotendinous junction regeneration and to preliminarily verify its osteogenic and tenogenic abilities in vitro. Methods: A polycaprolactone (PCL) scaffold with aligned and orthogonal fibers was created using melt electrowriting (MEW) and fused deposition modeling (FDM). The scaffold was coated with Type I collagen, and hydroxyapatite was carefully added to separate the regions intended for bone and tendon regeneration, before being rolled into a cylindrical shape. Human adipose-derived stem cells (hADSCs) were seeded to evaluate viability and differentiation. Scaffold characterization was performed with Scanning Electron Microscope (SEM). Osteogenesis was assessed by alkaline phosphatase (ALP) and Alizarin red staining, while immunostaining and transcription-quantitative polymerase chain reaction (RT-qPCR) evaluated osteogenic and tendogenic markers. Results: Scaffolds were developed in four variations: aligned (A), collagen-coated aligned (A+C), orthogonal (O), and mineral-coated orthogonal (O+M). SEM analysis confirmed surface morphology and energy-dispersive X-ray spectroscopy (EDS) verified mineral coating on O+M types. Hydrophilicity and mechanical properties were optimized in modified scaffolds, with A+C showing increased tensile strength and O+M improved in compression. hADSCs demonstrated good viability and morphology across scaffolds, withO+M scaffolds showing higher cell proliferation and osteogenic potential, and A and A+C scaffolds supporting tenogenic differentiation. Conclusion: This study confirms the potential of a novel PCL scaffold with distinct regions for osteogenic and tenogenic differentiation, supporting the regeneration of osteotendinous junctions in vitro.

Plasma surface modification of electrospun polyhydroxybutyrate (PHB) nanofibers to investigate their performance in bone tissue engineering.

Polyhydroxybutyrate (PHB) is a natural-source biopolymer of the polyhydroxyalkanoate (PHA) family. Nanofibrous scaffolds prepared from this biological macromolecule have piqued the interest of researchers in recent years due to their unique properties. Nonetheless, these nanofibers continue to have problems such as low surface roughness and high hydrophobicity. In this research, PHB nanofibers were produced by the electrospinning method. Following that, the surface of nanofibers was modified by atmospheric plasma. Scanning electron microscopy (SEM), water contact angle (WCA), atomic force microscopy (AFM), tensile test, and cell behavior analyses were performed on mats to investigate the performance of treated and untreated samples. The achieved results showed a lower water contact angle (from ≃120° to 43°), appropriate degradation rate (up to ≃20 % weight loss in four months), and outstanding biomineralization (Ca/P ratio of ≃1.86) for the modified sample compared to the neat PHB. Finally, not only the MTT test show better viability of MG63 osteoblast cells, but also Alizarin staining, ALP, and SEM results likewise showed better cell proliferation in the presence of modified mats. These findings back up the claim that plasma surface modification is a quick, environmentally friendly, and low-cost way to improve the performance of nanofibers in bone tissue engineering.

Sandwich-like electro-conductive polyurethane-based gelatin/soybean oil nanofibrous scaffolds with a targeted release of simvastatin for cardiac tissue engineering.

Cardiac tissue engineering (CTE) is a promising way for the restoration of injured cardiac tissue in the healthcare system. The development of biodegradable scaffolds with appropriate chemical, electrical, mechanical, and biological properties is an unmet need for the success of CTE. Electrospinning is a versatile technique that has shown potential applications in CTE. Herein, four different types of multifunctional scaffolds, including synthetic-based poly (glycerol sebacate)-polyurethane (PGU), PGU-Soy scaffold, and a series of trilayer scaffolds containing two outer layers of PGU-Soy and a middle (inner) layer of gelatin (G) as a natural and biodegradable macromolecule without simvastatin (S) and with simvastatin (GS), an anti-inflammatory agent, were fabricated in the sandwich-like structure using electrospinning technique. This approach offers a combination of the advantages of both synthetic and natural polymers to enhance the bioactivity and the cell-to-cell and cell-to-matrix intercommunication. An in vitro drug release analysis was performed after the incorporation of soybean oil (Soy) and G. Soy is used as a semiconducting material was introduced to improve the electrical conductivity of nanofibrous scaffolds. The physicochemical properties, contact angle, and biodegradability of the electrospun scaffolds were also assessed. Moreover, the blood compatibility of nanofibrous scaffolds was studied through activated partial thromboplastin time (APTT), prothrombin time (PT), and hemolytic assay. The results showed that all scaffolds exhibited defect-free morphologies with mean fiber diameters in the range of 361 ± 109 to 417 ± 167 nm. A delay in blood clotting was observed, demonstrating the anticoagulant nature of nanofibrous scaffolds. Furthermore, rat cardiomyoblast cell lines (H9C2) were cultured on scaffolds for 7 days, and the morphology and cell arrangement were monitored. Data indicated an appropriate cytocompatibility. Of note, in the PGU-Soy/GS nanofibrous scaffold, a high survival rate was indicated compared to other groups. Our findings exhibited that the simvastatin-loaded polymeric system had positive effects on cardiomyoblasts attachment and growth and could be utilized as a drug release carrier in the field of CTE.

Biomechanical Scaffolds of Decellularized Heart Valves Modified by Electrospun Polylactic Acid.

Enhancing the mechanical properties and cytocompatibility of decellularized heart valves is the key to promote the application of biological heart valves. In order to further improve the mechanical properties, the electrospinning and non-woven processing methods are combined to prepare the polylactic acid (PLA)/decellularized heart valve nanofiber-reinforced sandwich structure electrospun scaffold. The effect of electrospinning time on the performance of decellularized heart valve is investigated from the aspects of morphology, mechanical properties, softness, and biocompatibility of decellularized heart valve. Results of the mechanical tests show that compared with the pure decellularized heart valve, the mechanical properties of the composite heart valve were significantly improved with the tensile strength increasing by 108% and tensile strain increased by 571% when the electrospinning time exceeded 2 h. In addition, with this electrospinning time, the composite heart valve has a certain promoting effect on the human umbilical vein endothelial cells proliferation behavior. This work provides a promising foundation for tissue heart valve reendothelialization to lay the groundwork for organoid.

Effect of Sterilization Methods on Electrospun Scaffolds Produced from Blend of Polyurethane with Gelatin.

Fibrous polyurethane-based scaffolds have proven to be promising materials for the tissue engineering of implanted medical devices. Sterilization of such materials and medical devices is an absolutely essential step toward their medical application. In the presented work, we studied the effects of two sterilization methods (ethylene oxide treatment and electron beam irradiation) on the fibrous scaffolds produced from a polyurethane-gelatin blend. Scaffold structure and properties were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), infrared spectroscopy (FTIR), a stress-loading test, and a cell viability test with human fibroblasts. Treatment of fibrous polyurethane-based materials with ethylene oxide caused significant changes in their structure (formation of glued-like structures, increase in fiber diameter, and decrease in pore size) and mechanical properties (20% growth of the tensile strength, 30% decline of the maximal elongation). All sterilization procedures did not induce any cytotoxic effects or impede the biocompatibility of scaffolds. The obtained data determined electron beam irradiation to be a recommended sterilization method for electrospun medical devices made from polyurethane-gelatin blends.

Biomimetic Electrospun Scaffold-Based In Vitro Model Resembling the Hallmarks of Human Myocardial Fibrotic Tissue.

Adverse remodeling post-myocardial infarction is hallmarked by the phenotypic change of cardiac fibroblasts (CFs) into myofibroblasts (MyoFs) and over-deposition of the fibrotic extracellular matrix (ECM) mainly composed by fibronectin and collagens, with the loss of tissue anisotropy and tissue stiffening. Reversing cardiac fibrosis represents a key challenge in cardiac regenerative medicine. Reliable in vitro models of human cardiac fibrotic tissue could be useful for preclinical testing of new advanced therapies, addressing the limited predictivity of traditional 2D cell cultures and animal in vivo models. In this work, we engineered a biomimetic in vitro model, reproducing the morphological, mechanical, and chemical cues of native cardiac fibrotic tissue. Polycaprolactone (PCL)-based scaffolds with randomly oriented fibers were fabricated by solution electrospinning technique, showing homogeneous nanofibers with an average size of 131 ± 39 nm. PCL scaffolds were then surface-functionalized with human type I collagen (C1) and fibronectin (F) by dihydroxyphenylalanine (DOPA)-mediated mussel-inspired approach (PCL/polyDOPA/C1F), in order to mimic fibrotic cardiac tissue-like ECM composition and support human CF culture. BCA assay confirmed the successful deposition of the biomimetic coating and its stability during 5 days of incubation in phosphate-buffered saline. Immunostaining for C1 and F demonstrated their homogeneous distribution in the coating. AFM mechanical characterization showed that PCL/polyDOPA/C1F scaffolds, in wet conditions, resembled fibrotic tissue stiffness with an average Young's modulus of about 50 kPa. PCL/polyDOPA/C1F membranes supported human CF (HCF) adhesion and proliferation. Immunostaining for α-SMA and quantification of α-SMA-positive cells showed HCF activation into MyoFs in the absence of a transforming growth factor ß (TGF-ß) profibrotic stimulus, suggesting the intrinsic ability of biomimetic PCL/polyDOPA/C1F scaffolds to sustain the development of cardiac fibrotic tissue. A proof-of-concept study making use of a commercially available antifibrotic drug confirmed the potentialities of the developed in vitro model for drug efficacy testing. In conclusion, the proposed model was able to replicate the main hallmarks of early-stage cardiac fibrosis, appearing as a promising tool for future preclinical testing of advanced regenerative therapies.

Electrospun Scaffolds Enriched with Nanoparticle-Associated DNA: General Properties, DNA Release and Cell Transfection.

Biomaterial-mediated, spatially localized gene delivery is important for the development of cell-populated scaffolds used in tissue engineering. Cells adhering to or penetrating into such a scaffold are to be transfected with a preloaded gene that induces the production of secreted proteins or cell reprogramming. In the present study, we produced silica nanoparticles-associated pDNA and electrospun scaffolds loaded with such nanoparticles, and studied the release of pDNA from scaffolds and cell-to-scaffold interactions in terms of cell viability and pDNA transfection efficacy. The pDNA-coated nanoparticles were characterized with dynamic light scattering and transmission electron microscopy. Particle sizes ranging from 56 to 78 nm were indicative of their potential for cell transfection. The scaffolds were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, stress-loading tests and interaction with HEK293T cells. It was found that the properties of materials and the pDNA released vary, depending on the scaffold's composition. The scaffolds loaded with pDNA-nanoparticles do not have a pronounced cytotoxic effect, and can be recommended for cell transfection. It was found that (pDNA-NPs) + PEI9-loaded scaffold demonstrates good potential for cell transfection. Thus, electrospun scaffolds suitable for the transfection of inhabiting cells are eligible for use in tissue engineering.

Quaternized chitosan/PVA/natural bioactive agent electrospun wound scaffolds: production, characterization, and investigation of release kinetics.

Quaternized chitosan (HTCC) was synthesized and characterized to increase chitosan solubility. Then HTCC was electrospun with poly (vinyl alcohol) (PVA) and prepared natural bioactive agent (Calendula officinalis) extract was loaded onto fibers for wound scaffold applications. Morphological, structural, and mechanical characterization of the produced wound scaffolds was performed and their in vitro bioactive component release behavior was investigated. As a result, it was observed that the degree of quaternization of chitosan was 0.89, and synthesized HTCC was soluble in acidic, basic, alkaline media and could be electrospun with PVA in the presence of a natural bioactive agent. The presence of HTCC increased Young's modulus and the tensile strength of the PVA scaffolds, while the presence of bioactive extract caused a decrease in Young's modulus and an increase in tensile strength. Calendula officinalis is released in a controlled and slow manner from the scaffolds within approximately 55 h. The release behavior was consistent with the Higuchi kinetic model. In this study, the effect of PVA cooperator on HTCC nanofiber production in the presence of a bioactive component was investigated for the first time. HTCC and Calendula officinalis extract were also used together for the first time in the composition of a fiber scaffold. The mechanical properties and release kinetics of these scaffolds were also investigated for the first time. According to the results, it is thought that the wound scaffolds produced have the potential to be used as a new treatment tool, especially for chronic wounds.

Bioinspired electrospun decellularized extracellular matrix scaffolds promote muscle regeneration in a rat skeletal muscle defect model.

Volumetric muscle loss is a debilitating injury that can leave patients with long-lasting or permanent structural and functional deficits. With clinical treatments failing to address these shortcomings, there is a great need for tissue-engineered therapies to promote skeletal muscle regeneration. In this study, we aim to assess the potential for electrospun decellularized skeletal muscle extracellular matrix (dECM) to promote skeletal muscle regeneration in a rat partial thickness tibialis anterior defect model. Aligned electrospun scaffolds with varying degrees of crosslinking density were implanted into the defect site and compared to an empty defect control. After 8 weeks, muscles were harvested, weighed, and cellular and morphological analyses were performed via histology and immunohistochemistry. Cell infiltration, angiogenesis, and myogenesis were observed in the defect site in both dECM groups. However, favorable mechanical properties and slower degradation kinetics resulted in greater support of tissue remodeling in the more crosslinked scaffolds and preservation of existing myofiber area in both dECM groups compared to the empty defect control. More sustained release of pro-regenerative degradation products also promoted greater myofiber formation in the defect site. This study allowed for a greater understanding of how electrospun skeletal muscle scaffolds interact with existing skeletal muscle and can inform their potential as a therapy in a wide variety of soft tissue applications.

Flake Graphene as an Efficient Agent Governing Cellular Fate and Antimicrobial Properties of Fibrous Tissue Engineering Scaffolds-A Review.

Although there are several methods for fabricating nanofibrous scaffolds for biomedical applications, electrospinning is probably the most versatile and feasible process. Electrospinning enables the preparation of reproducible, homogeneous fibers from many types of polymers. In addition, implementation of this technique gives the possibility to fabricated polymer-based composite mats embroidered with manifold materials, such as graphene. Flake graphene and its derivatives represent an extremely promising material for imparting new, biomedically relevant properties, functions, and applications. Graphene oxide (GO) and reduced graphene oxide (rGO), among many extraordinary properties, confer antimicrobial properties of the resulting material. Moreover, graphene oxide and reduced graphene oxide promote the desired cellular response. Tissue engineering and regenerative medicine enable advanced treatments to regenerate damaged tissues and organs. This review provides a reliable summary of the recent scientific literature on the fabrication of nanofibers and their further modification with GO/rGO flakes for biomedical applications.

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.

Collagen Modified Anisotropic PLA Scaffold as a Base for Peripheral Nerve Regeneration.

Reconstruction of damaged nerves remains a significant unmet challenge in clinical medicine. Topographical and mechanical stimulations play important roles to repair peripheral nerve injury. The synergistic effects of topography and mechanical rigidity may significantly accelerate nerve regeneration. In this work, a nerve-guiding collagen/polylactic acid (PLA) electrospun scaffold is developed to facilitate peripheral nerve repair. The obtained anisotropic PLA electrospun scaffolds simulate the directional arranged structure of nerve realistically and promote axonal regeneration after sciatic nerve injury when compared with the isotropic PLA electrospun scaffolds. Moreover, the collagen-modified PLA electrospun scaffolds further provide sufficient mechanical support and favorable microenvironment for axon regeneration. In addition, it is observed that collagen-modified PLA electrospun scaffolds facilitate the axon regeneration by regulating Yes-associated protein (YAP) molecular pathway. Taken together, the engineered collagen-modified anisotropic PLA electrospun scaffolds may be a potential candidate to combine topography and mechanical rigidity for peripheral nerve regeneration is engineered.