Current studies based on regenerative medicine suggest, decellularized extracellular matrix (DC-ECM) components can regulate cell phenotype. In this regard, it is believed, presence of cartilage extracellular matrix particles in culture condition could produce physical and biochemical supportive cues for chondrogenesis. In this study, DC-ECM nanoparticles with average size of 61.5± 22.4 nm were produced by decellularization and mechanical processing. Homogenous distribution and nanoscale size of yield particles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopy imaging. Chemical structure preservation of cartilage ECM after decellularization was also confirmed by typical Fourier transform infrared (FTIR) spectrum mapping. The influence these nanoparticles on chondrogenic response of chondrocyte cells was investigated by direct and indirect addition of nanoparticles to culture medium. A clinical devitalized cartilage powder (DV-ECM) was also used as a positive control. Totally, MTS results showed that direct and indirect presence of both DC-ECM and DV-ECM particles in culture medium enhanced cellular metabolic activity except on day one of culture. Furthermore, on day 21, SOX9 and COL2 expression of cultured chondrocytes in the medium containing DC-ECM nanoparticles were up-regulated in comparison to negative control, which was further confirmed by presence more frequent number of larger size lacunae in micromass spheroids. Our findings support the use of ECM nanoparticles as condition supplement in culture medium and injectable biomaterials, especially for cell-based therapies for cartilage regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2463-2471, 2018.

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Iranian Gum Tragacanth (IGT) is among the most natural polymers which has interesting properties such as nontoxic nature, biodegradability and high resistance to bacterial attacks making it applicable for tissue scaffolds, protective clothing, and wound healing. In the current work, polyvinyl alcohol (PVA)/IGT nanocomposite fibre is prepared by using the electrospinning (ELS) technique in an aqueous solution with different volume ratios of 60/40, 70/30, 80/20, and 90/10. To enhance the chemical and mechanical stability of the produced samples, different amounts of nanoclay powder (1% and 3%) are added also to the solution. The blended nanofibres are characterized by scanning electron microscopy (SEM), Fouriertransform infrared (FTIR), and bioactivity evaluation in phosphate buffered saline (PBS) and simulated body fluid (SBF) solutions. The FTIR analysis indicated that PVA and IGT may have H + bonding interactions. The results revealed that with a higher amount of IGT, a superior degradation as well as a higher chemical and biological stability could be obtained in the nanobiocomposite blend fibres. Furthermore, the blend nanofibre samples of 80/20 and 3% nanoclay powder exhibit a significant improvement during evaluation of its properties.

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In this study, a thin layer with a thickness of about 120 μm of poly(caprolactone) (PCL) was fabricated by electrospinning method. Then, a fibrous nanocomposite composed of PCL/silk fibroin/strontium carbonate (PCL/SF/SrCO3) was electrospun on the prepared layer. Then, they were characterized. The mechanical properties, water uptake, degradation rate, wettability, porosity, and bioactivity of the electrospun membrane were scrutinized in vitro. Cytotoxicity of the samples was assessed by using osteoblast‐like cells (SAOS‐2) and L929 fibroblasts. Moreover, the cell adhesion, alkaline phosphatase (ALP) activity, and calcium deposition through alizarin red staining were conducted. Results revealed that the bilayer structure doubled the optimum mechanical properties and the addition of SrCO3 up to 15%–20% increased ALP activity, calcium deposition, and bioactivity. According to the results, the nanofibrous bilayer membrane containing 20 wt% SrCO3, 20 wt% SF, and 60 wt% PCL was chosen as the optimum sample. Therefore, this membrane could be applied in guided bone regeneration (GBR).