Construction of organ of Corti organoid to study the effects of berberine sulfate on damaged auditory cells.

Sensorineural hearing loss (SNHL) is mainly caused by injury or loss of hair cells (HCs) and associated spiral ganglion neurons (SGNs) in the inner ear. At present, there is still no effective treatment for SNHL in clinic. Recently, advances in organoid bring a promising prospect for research and treatment of SNHL. Meanwhile, three-dimensional (3D) printing provides a tremendous opportunity to construct versatile organoids for tissue engineering and regenerative medicine. In this study, gelatin (Gel), sodium alginate (SA), and polyvinyl alcohol (PVA) were used to fabricate biomimetic scaffold through 3D printing. The organ of Corti derived from neonatal mice inner ear was seeded on the PVA/Gel/SA scaffold to construct organ of Corti organoid. Then, the organ of Corti organoid was used to study the potential protective effects of berberine sulfate on neomycin-juried auditory HCs and SGNs. The results showed that the PVA/Gel/SA biomimetic 3D scaffolds had good cytocompatibilities and mechanical properties. The constructed organoid could maintain organ of Corti activity well in vitro. In addition, the injury intervention results showed that berberine sulfate could significantly inhibit neomycin-induced HC and SGN damage. This study suggests that the fabricated organoid is highly biomimetic to the organ of Corti, which may provide an effective model for drug development, cell and gene therapy for SNHL.

Antioxidative, Anti-Inflammatory, Antibacterial, Photo-Cross-Linkable Hydrogel of Gallic Acid-Chitosan Methacrylate: Synthesis, In Vitro, and In Vivo Assessments.

Chitosan (CS)-based photo-cross-linkable hydrogels have gained increasing attention in biomedical applications. In this study, we grafted CS with gallic acid (GA) by carbodiimide chemistry to prepare the GA-CS conjugate, which was subsequently modified with methacrylic anhydride (MA) modification to obtain the methacrylated GA-CS conjugate (GA-CS-MA). Our results demonstrated that the GA-CS-MA hydrogel not only exhibited improved physicochemical properties but also showed antibacterial, antioxidative, and anti-inflammatory capacity. It showed moderate antibacterial activity and especially showed a more powerful inhibitory effect against Gram-positive bacteria. It modulated macrophage polarization, downregulated pro-inflammatory gene expression, upregulated anti-inflammatory gene expression, and significantly reduced reactive oxygen species (ROS) and nitric oxide (NO) production under lipopolysaccharide (LPS) stimulation. Subcutaneously implanted GA-CS-MA hydrogels induced significantly lower inflammatory responses, as evidenced by less inflammatory cell infiltration, thinner fibrous capsule, and predominately promoted M2 polarization. This study provides a feasible strategy to prepare CS-based photo-cross-linkable hydrogels with improved physicochemical properties for biomedical applications.

Oriented polyaniline/poly-l-lactic acid/gelatin nanofiber scaffolds promote outgrowth of spiral ganglion neurons.

Sensorineural hearing loss (SNHL) is caused by the loss of sensory hair cells (HCs) and/or connected spiral ganglion neurons (SGNs). The current clinical conventional treatment for SNHL is cochlear implantation (CI). The principle of CI is to bypass degenerated auditory HCs and directly electrically stimulate SGNs to restore hearing. However, the effectiveness of CI is limited when SGNs are severely damaged. In the present study, oriented nanofiber scaffolds were fabricated using electrospinning technology to mimic the SGN spatial microenvironment in the inner ear. Meanwhile, different proportions of polyaniline (PANI), poly-l-lactide (PLLA), gelatin (Gel) were composited to mimic the composition and mechanical properties of auditory basement membrane. The effects of oriented PANI/PLLA/Gel biomimetic nanofiber scaffolds for neurite outgrowth were analyzed. The results showed the SGNs grew in an orientation along the fiber direction, and the length of the protrusions increased significantly on PANI/PLLA/Gel scaffold groups. The 2% PANI/PLLA/Gel group showed best effects for promoting SGN adhesion and nerve fiber extension. In conclusion, the biomimetic oriented nanofiber scaffolds can simulate the microenvironment of SGNs as well as promote neurite outgrowth in vitro, which may provide a feasible research idea for SGN regeneration and even therapeutic treatments of SNHL in future.

Berberine protects against neomycin-induced ototoxicity by reducing ROS generation and activating the PI3K/AKT pathway.

In mammals, aminoglycoside antibiotic-induced injury to hair cells (HCs) and associated spiral ganglion neurons (SGNs) is irreversible and eventually leads to permanent hearing loss. Efforts have been directed towards the advancement of efficacious therapeutic treatments to protect hearing loss, but the ideal substance for treating the damaged cochlear sensory epithelium has yet to be identified. Berberine (BBR), a quaternary ammonium hydroxide extracted from Coptis chinensis, has been found to display potential anti-oxidant and neuroprotective properties. However, its involvement in aminoglycoside antibiotic-induced ototoxicity has yet to be explored or assessed. In the present study, we explored the possible anti-oxidative properties of BBR in mitigating neomycin-triggered ototoxicity. An improved survival of HCs and SGN nerve fibers (NFs) in organ of Corti (OC) explants after neomycin with BBR co-treatment was observed, and BBR treatment attenuated reactive oxygen species (ROS) generation and reduced cleaved caspase-3 signaling by activating six phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling relative subtypes, and the addition of PI3K/AKT suppressor LY294002 resulted in a decrease in the protective effect. The protective effect of BBR against ototoxicity was also evident in a neomycin-injured animal model, as evidenced by the preservation of HC and SGN in mice administered subcutaneous BBR for 7 days. In summary, all results suggest that BBR has potential as a new and effective otoprotective agent, operating via the PI3K/AKT signaling pathway.

Mouse Embryonic Fibroblasts-Derived Extracellular Matrix Facilitates Expansion of Inner Ear-Derived Cells.

OBJECTIVE: Previous reports showed that mouse embryonic fibroblasts (MEFs) could support pluripotent stem cell selfrenewal and maintain their pluripotency. The goal of this study was to reveal whether the decellularized extracellular matrix derived from MEFs (MEF-ECM) is beneficial to promote the proliferation of inner ear-derived cells. MATERIALS AND METHODS: In this experimental study, we prepared a cell-free MEF-ECM through decellularization. Scanning electron microscope (SEM) and immunofluorescent staining were conducted for phenotype characterization. Organs of Corti were dissected from postnatal day 2 and the inner ear-derived cells were obtained. The identification of inner ear-derived cells was conducted by using reverse transcription-polymerase chain reaction (RT-PCR). Cell counting kit-8 (CCK-8) was used to evaluate the proliferation capability of inner ear-derived cells cultured on the MEFECM and tissue culture plate (TCP). RESULTS: The MEF-ECM was clearly observed after decellularization via SEM, and the immunofluorescence staining results revealed that MEF-ECM was composed of three proteins, including collagen I, fibronectin and laminin. Most importantly, the results of CCK-8 showed that compared with TCP, MEF-ECM could effectively facilitate the proliferation of inner ear-derived cells. CONCLUSION: The discovery of the potential of MEF-ECM in promoting inner ear-derived cell proliferation indicates that the decellularized matrix microenvironment may play a vital role in keeping proliferation ability of these cells. Our findings indicate that the use of MEF-ECM may serve as a novel approach for expanding inner ear-derived cells and potentially facilitating the clinical application of inner ear-derived cells for hearing loss in the future.

Chicken utricle stromal cell-derived decellularized extracellular matrix coated nanofibrous scaffolds promote auditory cell production.

Stem cell therapy has a broad future in treating sensorineural hearing loss in mammals. But how to produce sufficient functional auditory cells including hair cells, supporting cells as well as spiral ganglion neurons from potential stem cells is the bottleneck. In this study, we aimed to simulate inner ear development microenvironment to induce inner ear stem cells to differentiate into auditory cells. The different mass ratios of poly-l-lactic acid/gelatin (PLLA/Gel) scaffolds were fabricated by electrospinning technology to mimic the structure of the native cochlear sensory epithelium. The chicken utricle stromal cells were isolated and cultured, and then seeded on the PLLA/Gel scaffolds. The chicken utricle stromal cell-derived decellularized extracellular matrix (U-dECM)-coated PLLA/Gel bioactive nanofiber scaffolds (U-dECM/PLLA/Gel) were prepared by decellularization. The U-dECM/PLLA/Gel scaffolds were used for culture of inner ear stem cells, and the effects of the modified scaffolds on the differentiation of inner ear stem cells were analyzed by RT-PCR and immunofluorescent staining. The results showed that U-dECM/PLLA/Gel scaffolds possessed good biomechanical properties can significantly promote the differentiation of inner ear stem cells and make them differentiate into auditory cells. Collectively, these findings indicated that U-dECM-coated biomimetic nanomaterials may be a promising strategy for auditory cell production.

Incorporation of magnesium oxide nanoparticles into electrospun membranes improves pro-angiogenic activity and promotes diabetic wound healing.

Deficient angiogenesis is the major abnormality impairing the healing process of diabetic wounds. Electrospun nanofiber membranes have shown promise for wound dressing. A prerequisite for electrospun membranes to treating diabetic wounds is the capacity to promote angiogenesis of wounds. Current approaches are mainly focused on the use of pro-angiogenic growth factors to enhance the angiogenic properties of electrospun membranes. Despite improved angiogenesis, both the incorporation of growth factors into electrospun nanofibers and maintenance of its activity in the long term is of technical difficulty. We herein report an electrospun membrane made of polycaprolactone (PCL)/gelatin/magnesium oxide (MgO) nanoparticles (PCL/gelatin/MgO), which releases magnesium ions (Mg2+) to enhance angiogenesis. MgO-incorporated membranes promote the proliferation of human umbilical vein endothelial cells and upregulate vascular endothelial growth factor (VEGF) production in vitro. Subcutaneous implantation study in a rat model demonstrates that the MgO-incorporated membrane shows a faster degradation profile and elicits moderate immune responses that gradually resolve. Upon subcutaneous implantation, PCL/gelatin/MgO membranes allow robust blood vessel formation as early as one week after surgery, and the newly formed capillary networks enrich within the degrading membrane over time. PCL/gelatin/MgO membranes significantly accelerated diabetic wound healing by suppressing inflammatory responses, promoting angiogenesis, and boosting granulation formation. Taken together, these results are implicative to rationally designing magnesium-incorporated electrospun membranes with improved pro-angiogenic activity for treating diabetic wounds.

Osteoblast-derived extracellular matrix coated PLLA/silk fibroin composite nanofibers promote osteogenic differentiation of bone mesenchymal stem cells.

Poly-L-lactic acid (PLLA) is one of the most commonly used synthetic materials for regenerative medicine, and silk fibroin (SF) is a natural protein with excellent biocompatibility. Combination of PLLA and SF in a proper proportion by electrospinning may generate composite nanofibers that could meet the requirements of scaffolding in bone tissue engineering. The application of PLLA/SF nanofibrous scaffold for osteogenesis is well established in vitro and in vivo. However, PLLA/SF nanofibrous scaffold does not have an ideal ability to promote cell adhesion, proliferation, and differentiation. Extracellular matrix (ECM) plays a critical role in modulating cellular behavior. However, the role of combination of natural ECM with nanofibrous scaffold in regulating osteogenic differentiation is unclear. In this study, we aimed to develop a novel composite PLLA/SF nanofibrous scaffold coated with osteoblast-derived extracellular matrix (O-ECM/PLLA/SF) and analyze the effects of the modified scaffold on osteogenic differentiation of BMSCs. The surface structural features and compositions of the O-ECM/PLLA/SF scaffold were characterized by SEM and immunofluorescence staining. The capacities of the O-ECM/PLLA/SF scaffold to induce osteogenic differentiation of BMSCs were investigated by alkaline phosphatase (ALP) and alizarin red staining (ARS). The results showed BMSCs cultured on O-ECM/PLLA/SF scaffold significantly increased osteogenic differentiation compared with cells cultured individually on a scaffold or O-ECM. Collectively, these findings indicate that O-ECM-coated nanofibrous scaffold can be a promising strategy for osteogenic differentiation of BMSCs, opening a new possibility of utilizing composite scaffolds for bone tissue engineering.

Magnesium oxide-incorporated electrospun membranes inhibit bacterial infections and promote the healing process of infected wounds.

Bacterial infections cause severe secondary damage to wounds and hinder wound healing processes. We prepared magnesium oxide (MgO) nanoparticle-incorporated nanofibrous membranes by electrospinning and investigated their potential for wound dressing and fighting bacterial infection. MgO-Incorporated membranes possessed good elasticity and flexibility similar to native skin tissue and were hydrophilic, ensuring comfortable contact with wound beds. The cytocompatibility of membranes was dependent on the amounts of incorporated MgO nanoparticles: lower amounts promoted while higher amounts suppressed the proliferation of fibroblasts, endothelial cells, and macrophages. The antibacterial capacity of membranes was proportional to the amounts of incorporated MgO nanoparticles and they inhibited more than 98% E. coli, 90% S. aureus, and 94% S. epidermidis. MgO nanoparticle-incorporated membranes effectively suppressed bacterial infection and significantly promoted the healing processes of infected full-thickness wounds in a rat model. Subcutaneous implantation demonstrated that the incorporation of MgO nanoparticles into electrospun membranes elevated their bioactivity as evidenced by considerable cell infiltration into their dense nanofiber configuration and enhanced the remodeling of implanted membranes. This study highlights the potential of MgO-incorporated electrospun membranes in preventing bacterial infections of wounds.

Conditioned Medium Enhances Osteogenic Differentiation of Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells.

Background: Recent studies have shown that induced pluripotent stem cells (iPSCs) could be differentiated into mesenchymal stem cells (MSCs) with notable advantages over iPSCs per se. In order to promote the application of iPSC-MSCs for osteoregenerative medicine, the present study aimed to assess the ability of murine iPSC-MSCs to differentiate into osteoblast phenotype. Methods: Osteogenic differentiation medium, blending mouse osteoblast-conditioned medium (CM) with basic medium (BM) at ratio 3:7, 5:5 and 7:3, were administered to iPSC-MSCs, respectively. After 14 days, differentiation was evaluated by lineage-specific morphology, histological stain, quantitative reverse transcription-polymerase chain reaction and immunostaining. Results: The osteogenesis-related genes, alp, runx2, col1 and ocn expressions suggest that culture medium consisting of CM:BM at the ratio of 3:7 enhanced the osteogenic differentiation more than other concentrations that were tested. In addition, the alkaline phosphatase activity and osteogenic marker Runx2 expression demonstrate that the combination of CM and BM significantly enhanced the osteogenic differentiation of iPSC-MSCs. Conclusion: In summary, this study has shown that osteoblast-derived CM can dramatically enhance osteogenic differentiation of iPSC-MSCs toward osteoblasts. Results from this work will contribute to optimize the osteogenic induction conditions of iPSC-MSCs and will assist in the potential application of iPSC-MSCs for bone tissue engineering.

Influence of 24-diamino-5-phenylthiazole on neomycin ototoxicity in cultured organ of Corti explants.

Hair cells do not undergo spontaneous regeneration when they are damaged in the mammalian organ of Corti, leading to irreversible hearing loss. Previous studies have shown that 24-diamino-5-phenylthiazole (DAPT), an inhibitor of Notch signaling, plays a major role in inner ear development. However, whether DAPT influences antibiotic-induced hair cell damage remains uncertain. The present study aimed to investigate whether DAPT exerts protective or regenerative effects on neomycin-damaged hair cells. A histological analysis was carried out to assess the number and morphological changes of hair cells in cultured organ of Corti explants. Our results showed that in-vitro treatment with DAPT induced extra hair cells, whereas no newly generated supporting cells were found. We also found that DAPT was effective for preventing hair cell loss when cotreatment with neomycin was performed, suggesting that DAPT exerted protective effects on neomycin ototoxicity. In addition, DAPT treatment for 2-4 days following neomycin damage induced supernumerary hair cells. These findings indicate that inhibition of Notch signaling is a possible strategy for the treatment of hair cell loss caused by aminoglycoside antibiotics.

Highly aligned core-shell structured nanofibers for promoting phenotypic expression of vSMCs for vascular regeneration.

This study was designed to assess the efficacy of hyaluronan (HA) functionalized well-aligned nanofibers of poly-l-lactic acid (PLLA) in modulating the phenotypic expression of vascular smooth muscle cells (vSMCs) for blood vessel regeneration. Highly aligned HA/PLLA nanofibers in core-shell structure were prepared using a novel stable jet electrospinning approach. Formation of a thin HA-coating layer atop each PLLA nanofiber surface endowed the uni-directionally oriented fibrous mats with increased anisotropic wettability and mechanical compliance. The HA/PLLA nanofibers significantly promoted vSMC to elongation, orientation, and proliferation, and also up-regulated the expression of contractile genes/proteins (e.g., α-SMA, SM-MHC) as well as the synthesis of elastin. Six weeks of in vivo scaffold replacement of rabbit carotid arteries showed that vascular conduits made of circumferentially aligned HA/PLLA nanofibers could maintain patency and promoted oriented vSMC regeneration, lumen endothelialization, and capillary formation. This study demonstrated the synergistic effects of nanotopographical and biochemical cues in one biomimetic scaffold design for efficacious vascular regeneration.

Osteogenic differentiation and bone regeneration of iPSC-MSCs supported by a biomimetic nanofibrous scaffold.

Induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) are a new type of MSCs that come with attractive merits over the iPSCs per se. Aimed for regenerating bone tissues, this study was designed to investigate osteogenic differentiation and bone regeneration capacities of iPSC-MSCs by using biomimetic nanofibers of hydroxyapatite/collagen/chitosan (HAp/Col/CTS). Murine iPSCs were firstly induced to differentiate into iPSC-MSCs and thoroughly characterized. Effects of HAp/Col/CTS nanofibers prepared from electrospinning of Col-doped HAp/CTS nanocomposite, on osteogenic differentiation of the generated iPSC-MSCs were then evaluated in detail, including cell morphology, proliferation, migration, quantified specific osteogenic gene and protein expressions. Compared with different controls (TCP, CTS, and HAp/CTS), the HAp/Col/CTS scaffold was found to have more favorable effects on attachment and proliferation of iPSC-MSCs than others (P<0.01). Expressions of osteogenic genes, Runx2, Ocn, Alp, and Col, were significantly upregulated in iPSC-MSCs cultured on HAp/Col/CTS than CTS (P<0.01). Similarly, there appeared considerably higher secreting activities of osteogenesis protein markers, ALP and Col. Furthermore, mouse cranial defects were created to investigate efficacy of using iPSC-MSCs in combination with HAp/Col/CTS scaffold for regenerative bone repair in vivo. Examinations by computed tomography (CT) imaging, bone mineral density and hematoxylin eosin (HE) staining corroborated that cell-scaffold construct of iPSC-MSCs+HAp/Col/CTS could effectively promote bone regeneration. After 6 weeks of implantation, bone mineral density of the iPSC-MSCs+HAp/Col/CTS group was found to be nearly 2-fold higher than others. Our results demonstrated that biomimetic nanofibers of HAp/Col/CTS promoted the osteogenic differentiation and bone regeneration of iPSC-MSCs. The iPSC-MSCs+HAp/Col/CTS complex could be used as a new 'stem cell-scaffold' system for realizing personalized and efficacious bone regeneration in future. STATEMENT OF SIGNIFICANCE: In bone tissue engineering, stem cells have become the most important source of seed cells. iPSC-MSCs are a new type of MSCs that come with attractive merits over the iPSCs per se. However, how to obtain befitting iPSC-MSCs and regulate their osteogenic differentiation are the key issues to be addressed. Given the great biomimicking capacity to extracellular matrix, electrospun nanofibers may be explored to modulate osteogenic differentiation of the iPSC-MSCs. This study successfully demonstrated that biomimetic nanofibers of HAp/Col/CTS significantly promoted the osteogenic differentiation and bone regeneration of iPSC-MSCs, which thereby suggests that nanofibrous scaffold supported iPSC-MSCs complex may be a new 'stem cell-scaffold' system for regulating the fate of osteogenic differentiation of iPSC-MSCs towards patient-specific bone regeneration in future.

Green electrospun grape seed extract-loaded silk fibroin nanofibrous mats with excellent cytocompatibility and antioxidant effect.

Silk fibroin (SF) from Bombyx mori has an excellent biocompatibility and thus be widely applied in the biomedical field. Recently, various SF-based composite nanofibers have been developed for more demanding applications. Additionally, grape seed extract (GSE) has been demonstrated to be powerful on antioxidation. In the present study, we dedicate to fabricate a GSE-loaded SF/polyethylene oxide (PEO) composite nanofiber by green electrospinning. Our results indicated the successful loading of GSE into the SF/PEO composite nanofibers. The introduction of GSE did not affect the morphology of the SF/PEO nanofibers and GSE can be released from the nanofibers with a sustained manner. Furthermore, comparing with the raw SF/PEO nanofibrous mats, the GSE-loaded SF/PEO nanofibrous mats significantly enhanced the proliferation of the skin fibroblasts and also protected them against the damage from tert-butyl hydroperoxide-induced oxidative stress. All these findings suggest a promising potential of this novel GSE-loaded SF/PEO composite nanofibrous mats applied in skin care, tissue regeneration and wound healing.

HAp incorporated ultrafine polymeric fibers with shape memory effect for potential use in bone screw hole healing.

In the clinical setting of bone fracture healing, hardware removal often causes localized microtrauma and residual screw holes may act as stress risers to place the patient at a risk of refracture. To address this noted issue, this study proposed to develop a biologically mimicking and mechanically self-actuated nanofibrous screw-like scaffold/implant for potential in situ bone regeneration. By incorporating nano-hydroxyapatite (HAp) into a shape memory copolymer poly(d,l-lactide-co-trimethylene carbonate) (PLMC) via co-electrospinning, composite nanofibers of HAp/PLMC with various HAp proportions (1, 2 and 3 wt%) were successfully generated. Morphological, thermal and mechanical properties as well as the shape memory effect of the resultant HAp/PLMC nanofibers were characterized using a variety of techniques. Thereafter, osteoblasts isolated from rat calvarial were cultured on the fibrous HAp/PLMC scaffold to assess its suitability for bone regeneration in vitro. We found that agglomerates gradually appeared on the fiber surface with increasing HAp loading fraction. The switching temperature for actuating shape recovery Ts (i.e., glass transition temperature Tg) of the fibrous HAp/PLMC was readily modulated to fall between 43.5 and 51.3 °C by varying the HAp loadings. Excellent shape memory properties were achieved for the HAp/PLMC composite nanofibers with a shape recovery ratio of Rr > 99% and shape fixity ratio of Rf > 99%, and the shape recovery force of the HAp/PLMC nanofibers was also strengthened compared to that of the HAp-free PLMC nanofibers. Moreover, we demonstrated that the engineered screw-like HAp/PLMC scaffold/implant (ϕ = 5 mm) was able to return from a slender bar to its original stumpy shape in a time frame of merely 8 s at 48 °C. Biological assay results corroborated that the incorporation of HAp to PLMC nanofibers significantly enhanced the alkaline phosphatase secretion as well as mineral deposition in bone formation. These attractive results warrant further investigation in vivo on the feasibility of applying the biomimicking nanofibrous HAp/PLMC scaffold with shape memory effect for bone screw hole healing.

Direct printing of patterned three-dimensional ultrafine fibrous scaffolds by stable jet electrospinning for cellular ingrowth.

Electrospinning has been widely used to produce ultrafine fibers in microscale and nanoscale; however, traditional electrospinning processes are currently beset by troublesome limitations in fabrication of 3D periodic porous structures because of the chaotic nature of the electrospinning jet. Here we report a novel strategy to print 3D poly(L-lactic acid) (PLLA) ultrafine fibrous scaffolds with the fiber diameter of approximately 2 µm by combining a stable jet electrospinning method and an X-Y stage technique. Our approach allows linearly deposited electrospun ultrafine fibers to assemble into 3D structures with tunable pore sizes and desired patterns. Process conditions (e.g., plotting speed, feeding rate, and collecting distance) were investigated in order to achieve stable jet printing of ultrafine PLLA fibers. The proposed 3D scaffold was successfully used for cell penetration and growth, demonstrating great potential for tissue engineering applications.

Genipin-crosslinked electrospun chitosan nanofibers: Determination of crosslinking conditions and evaluation of cytocompatibility.

To improve durability in wet conditions, electrospun chitosan (CTS) nanofibers were submersed into PBS (pH 7.4) solutions containing varied amounts of genipin (GP 0.1, 0.5, and 1% w/v) for crosslinking treatment. GP-crosslinking allowed the electrospun CTS nanofibers to maintain their fibrous morphology in wet state. Maximum tensile strength, 84.2% of the dry state strength, was attained when crosslinking was performed in GP 0.5% solution. GP-crosslinking also endowed the CTS nanofibers with enhanced resistances to swelling and enzymatic degradation. GP-crosslinked CTS nanofibers were found to significantly promote the adhesion and growth of the L929 fibroblasts, with the most suitable sample was the one crosslinked in the GP 0.5% solution as well. Our results suggest that crosslinking with the 0.5% GP in PBS could yield CTS nanofibers with improved wet stability in nanofiber structure and optimized mechanical and biological performances.

Induced Pluripotent Stem Cells as a new Strategy for Osteogenesis and Bone Regeneration.

Induced pluripotent stem (iPS) cells, possess high proliferation and differentiation ability, are now considered an attractive option for osteogenic differentiation and bone regeneration. In fact, recent discoveries have demonstrated that iPS cells can be differentiated into osteoblasts, suggesting that iPS cells have the potential to advance future bone regenerative therapies. Herein, we provide an overview of the recent findings on osteogenic characteristics and differentiation potential of iPS cells. In addition, we discuss current methods for inducing their specification towards osteogenic phenotype as well as in vivo evidence supporting the therapeutic benefit of iPS-derived osteoblasts. Finally, we describe recent findings regarding the use of iPS-derived cells for osteogenic differentiation and bone regeneration, which have indicated that these pluripotent cells represent an ideal tool for regenerative cell therapies and might contribute to the development of future bone tissue engineering.