Evaluation of rabbit adipose derived stem cells fate in perfused multilayered silk fibroin composite scaffold for Osteochondral repair.

Development of osteochondral tissue engineering approaches using scaffolds seeded with stem cells in association with mechanical stimulations has been recently considered as a promising technique for the repair of this tissue. In this study, an integrated and biomimetic trilayered silk fibroin (SF) scaffold containing SF nanofibers in each layer was fabricated. The osteogenesis and chondrogenesis of stem cells seeded on the fabricated scaffolds were investigated under a perfusion flow. 3-Dimethylthiazol-2,5-diphenyltetrazolium bromide assay showed that the perfusion flow significantly enhanced cell viability and proliferation. Analysis of gene expression by stem cells revealed that perfusion flow had significantly upregulated the expression of osteogenic and chondrogenic genes in the bone and cartilage layers and downregulated the hypertrophic gene expression in the intermediate layer of the scaffold. In conclusion, applying flow perfusion on the prepared integrated trilayered SF-based scaffold can support osteogenic and chondrogenic differentiation for repairing osteochondral defects.

An investigation into osteogenic differentiation effects of silk fibroin-nettle (Urtica dioica L.) nanofibers.

The purpose of this study was to investigate physical, mechanical, and osteogenic properties of silk fibroin (SF) nanofibers containing Urtica dioica L. (nettle) extract at different concentrations. In this respect, the successful incorporation of nettle in SF nanofibers was analyzed and then confirmed through Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The mean fiber diameter, water uptake, breaking strain, cellular attachment, and proliferation of the given nanofibers also increased as the nettle content was added, while this trend was opposite in terms of tensile strength and modulus. The in vitro release studies correspondingly demonstrated that the nettle release had been controlled according to Fickian diffusion and it was faster in the samples including more nettle. Furthermore, both ARS staining and real-time RT-PCR results suggested that nettle had enhanced the expression of both early and late markers of osteoblast differentiation in a dose-dependent manner.