Enhanced chondrogenic differentiation of bone marrow mesenchymal stem cells on gelatin/glycosaminoglycan electrospun nanofibers with different amount of glycosaminoglycan

Tissue engineering is a new technique to help damaged cartilage treatment using cells and scaffolds. In this study we tried to evaluate electrospun scaffolds composed of gelatin/glycosaminoglycan (G/GAG) blend nanofibers in chondrogenesis of bone marrow-derived mesenchymal stem cells (BMMSCs). Scaffolds were fabricated by electrospinning technique with different concentration of glycosaminoglycan (0, 5, 10, and 15) in gelatin matrix. BMMSCs were cultured on the scaffolds for chondrogenesis process. MTT assay was done for scaffold's biocompatibility and cells viability evaluation. Alcian blue staining was carried out to determine the release of GAG and reverse transcription polymerase chain reaction (RT-PCR) was done for expression of COL2A1 and also immunocytochemistry assay were used to confirm expression of type II collagen. Scaffold with 15 GAG showed better result for biocompatibility (p =0.02). Scanning electron microscopy (SEM) micrographs showed that MSCs have good attachment to the scaffolds. Alcian blue staining result confirmed that cells produce GAG during differentiation time different from GAG in the scaffolds. Also the results for RT-PCR showed the expression of COL2A1 marker. Immunocytochemistry assay for type II collagen confirm that this protein expressed. Scaffold comprising 15 GAG is better results for chondrogenesis and it can be a good applicant for cartilage tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 38�48, 2019. © 2018 Wiley Periodicals, Inc

Facile fabrication of sulfated alginate electrospun nanofibers

Mass fabrication of sodium alginate nanofibers using single-nuzzle electrospinning process is an open challenge mainly due to its inter- and intramolecular hydrogen bonding, rigid chain conformation and low solubility. In this regards, we synthesized sodium sulfated alginate (SSA) through sulfation of hydroxyl functional groups of alginate. Not only decreases the hydrogen bonding density through the sulfation reaction, but the sulfated alginate also demonstrates more solubility in aqueous media compared to the pristine alginate. Beside the sulfation of alginate, its electrospinnability in combination with polyvinyl alcohol (PVA) significantly improves. In contrast to the neat alginate, concentrated aqueous solutions of sulfated alginate, 10 wt, can be easily prepared and electrospun to obtain nanofibers of sulfated alginate. In this regards, facile fabrication of electrospun nanofibers of alginate derivatives with 50 wt content in dry electrospun mat of SSA/PVA using single-nuzzle electrospinning and flow rate of 5 mL h�1 was developed for the first time. © 2018 Elsevier Lt

Cardiac ECM/chitosan/alginate ternary scaffolds for cardiac tissue engineering application

Since cardiovascular diseases are the number one cause of death in worldwide, and the traditional treatments have limitations, the emergence of cardiac tissue engineering (CTE) can be a promising approach. In this study, scaffold fabrication from the solubilized cardiac extracellular matrix (ECM) accompanied with alginate and chitosan for CTE was carried out. The influence of blending ratios on chemical and physical properties of the scaffolds including FTIR spectroscopy, porosity, pore size, and their mechanical properties were investigated. The porosity of scaffolds was more than 96 with very high swelling rate while maintaining their stability in PBS solution. Blending ECM with chitosan and alginate significantly improve the tensile strength of ECM. FTIR spectrum of scaffolds demonstrated interaction of solubilized ECM with two opposite-charged polysaccharides. The proliferation of human mesenchymal stem cells (hMSCs) on the ternary scaffolds using MTS assay, revealed that blending ECM with polysaccharides at ratio of 75: 25 (E75/P25) led to improve the proliferation of hMSCs on scaffolds. Scanning electron microscope (SEM) revealed the porous structure and the presence of hMSCs cells inside the pores. In addition, histological analysis confirmed that cardiomyocyte penetration inside scaffolds after 7 days of culture. The immunofluorescence staining revealed that higher expression of cardiac marker (cTnT) in ternary scaffold in comparison with ECM. © 202

Electrospun polyvinyl alcohol/gelatin/chondroitin sulfate nanofibrous scaffold: Fabrication and in vitro evaluation

Electrospun nanofibers have attracted a lot of attention in recent years in tissue engineering applications. In this research, novel polyvinyl alcohol/gelatin/chondroitin sulfate (PVA/GE/Cs) nanofibrous scaffolds using non-carcinogen solvent system via electrospinning technique was evaluated. A solvent system containing water and acetic acid was used as a safe solvent system to obtain a homogenous mixture with suitable solvent properties and finally non-toxic nanofibrous scaffolds. The effect of water to the acetic acid ratio in the solvent system (7:3, 6:4, 5:5, 4:6, 3:7) and also polymer concentration (8, 9, 10 w/v ) on nanofibers morphology was investigated. The appropriate flow rate and voltage ranges to obtain uniform and bead-free electrospun scaffold were investigated. Effect of different Cs ratio (0, 10, 15 and 20 wt) on solution properties was evaluated. Influence of Cs ratio on chemical, physical and thermal properties of the electrospun scaffolds was studied. The results of cell toxicity indicated that prepared PVA/GE/Cs scaffolds have no cell toxicity. SEM results demonstrated that L929 mouse fibroblast cells have suitable interaction with scaffold surface and also attached and proliferated well on the prepared substrate after 24 and 48 h and also have a potential for using in tissue engineering. © 2018 Elsevier B.V

Electrospun polyvinyl alcohol/gelatin/chondroitin sulfate nanofibrous scaffold: Fabrication and in vitro evaluation

Electrospun nanofibers have attracted a lot of attention in recent years in tissue engineering applications. In this research, novel polyvinyl alcohol/gelatin/chondroitin sulfate (PVA/GE/Cs) nanofibrous scaffolds using non-carcinogen solvent system via electrospinning technique was evaluated. A solvent system containing water and acetic acid was used as a safe solvent system to obtain a homogenous mixture with suitable solvent properties and finally non-toxic nanofibrous scaffolds. The effect of water to the acetic acid ratio in the solvent system (7:3, 6:4, 5:5, 4:6, 3:7) and also polymer concentration (8, 9, 10 w/v ) on nanofibers morphology was investigated. The appropriate flow rate and voltage ranges to obtain uniform and bead-free electrospun scaffold were investigated. Effect of different Cs ratio (0, 10, 15 and 20 wt) on solution properties was evaluated. Influence of Cs ratio on chemical, physical and thermal properties of the electrospun scaffolds was studied. The results of cell toxicity indicated that prepared PVA/GE/Cs scaffolds have no cell toxicity. SEM results demonstrated that L929 mouse fibroblast cells have suitable interaction with scaffold surface and also attached and proliferated well on the prepared substrate after 24 and 48 h and also have a potential for using in tissue engineering. © 2018 Elsevier B.V

Synthesis methods of in situ forming injectable hydrogels and their applications in tissue engineering: A review

Tissue engineering is a triad involves three components of different types of cells, growth factor, small biomolecules and scaffold for the purpose of tissue restore, repair and regeneration. In tissue engineering, attachment, growth, proliferation and differentiation of cells require careful control of external factors such as the physical properties of the scaffold as extra cellular matrix (ECM), type and amount of biologically active molecules like small biomolecules, peptides and proteins. Therefore, the interaction of the synthetic and natural scaffolds with the cells must reflect the cellular microenvironment in the body. In this study, we describe a variety of in situ forming injectable hydrogels synthesis with the medical application and tissue regeneration that are crosslinked by chemical bonding or physical interactions. These types of hydrogels have attracted a lot of attention in tissue engineering applications because they can easily transfer the cells or delivered the biomolecules to the damaged tissue. Lack of severe toxicity, minimal injury and pain during surgery could be the other advantages of the injectable hydrogels. A wide variety of chemical methods have been used to crosslink the injectable hydrogels such as click chemistry, Michael addition, Schiff-base, enzymatic reaction and, etc. Some hydrogels can also be cross-linked using physical interactions such as ionic interactions, hydrogen bonding, supramolecular interaction, etc., without external factors in the physiological conditions of the body. In this study, in addition to various methods of synthesis, the practical aspects of hydrogels in regenerative medicine and their achievements in tissue engineering are discussed. © 2020 Iran Polymer Society. All rights reserved

Polyvinyl alcohol/sulfated alginate nanofibers induced the neuronal differentiation of human bone marrow stem cells

Scaffolds that are used for neural tissue engineering are fabricated to mimic the extracellular matrix. In this paper, we have fabricated polyvinyl alcohol/sulfated alginate (PVA/SA) nanofibers with different concentrations (10, 20 and 30 wt) of sulfated alginate by electrospinning technique. The average fibers diameters of 169�488 nm were achieved by electrospinning of polymers blend (PVA/SA). The results of the MTT assay and scanning electron microscopy showed that PVA/sulfated alginate nanofibrous scaffold with 30 wt SA provided more desirable surface attachment of C6, Schwann cells (SCs) and human bone marrow mesenchymal stem cells (hBMSCs). RT-PCR and immunocytochemistry for MAP-2 marker were conducted to confirm the neural-differentiation of hBMSCs. The expression of MAP-2 confirmed neural differentiation for up to 14 days. Our results showed that PVA/SA nanofibrous scaffold with 30 wt SA is a suitable substrate for mesenchymal stem cells growth and is capable of inducing neuronal differentiation. © 2019 Elsevier B.V

Tough, hybrid chondroitin sulfate nanofibers as a promising scaffold for skin tissue engineering

Fabrication of gelatin/polyvinyl alcohol/chondroitin sulfate (GEL/PVA/CS) hybrid nanofibrous scaffolds using acetic acid and water as an environmentally friendly solvent system via electrospinning for skin tissue engineering was investigated. Modeling and optimization of the nanofibers were performed using response surface methodology (RSM). The influence of CS ratio on mechanical, physical and biological properties of the nanofibers was studied. PVA was used as a carrier and enhancer of mechanical properties. The mechanical properties of hybrid nanofibers were investigated in dry and wet states. The results showed that in the cross-linked dry state the tensile strength was up to 4 MPa. In the wet state, nanofibers exhibited 200 elongation at break, indicating a toughness behavior which enhances the flexibility for clinical applications. Scanning electron microscope (SEM) confirmed the stability of nanofibrous morphology during degradation up to 21 days. Human dermal fibroblast-green fluorescent protein-positive (HDF-GFP+) cells were cultured on the scaffolds and results showed the appropriate biocompatibility. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was employed to study cell proliferation, and the results confirmed the positive effect of CS ratio on HDF cells attachment as well as proliferation on the nanofibers. Considering the results of in vitro assay, nanofibers containing 15 CS ratio suggested as an optimum CS ratio. © 201

Chondroitin sulfate immobilized PCL nanofibers enhance chondrogenic differentiation of mesenchymal stem cells

Cold Atmospheric Plasma (CAP) is used as a promising method in surface modification for immobilization of chondroitin sulfate functional biomacromolecules on PCL nanofibrous substrates for cartilage tissue engineering. The GAG-grafted scaffolds are able to successfully support the attachment and proliferation of mesenchymal stem cells (MSCs). The seeded scaffolds show the chondro-differentiation of MSCs during a 21-days cell culture in a non-differential medium. Expression of SOX9, Collagen10 and Collagen2 proved the chondro-inductive effect of GAG-grafted scaffolds. Besides, no external chondro-genic differential agent was used in the differentiation of MSCs to chondrocyte. The cells passed the last phase of chondrogenesis after 14 days of incubation. Thus, the GAG-fabricated fibrous scaffolds using CAP are potential candidates for cartilage tissue engineering. © 201