The evaluation of toxicity of carbon nanotubes on the human adipose-derived-stem cells in-vitro

Background: Carbon nanotubes (CNTs) have a large variety of applications in tissue engineering and biomedical devices. The biocompatibility and cytotoxicity of CNTs have been studied widely, however, up until now; there was uncertainty on how nanosized materials behave in the human body and stem cells. The current study describes the functionalized carbon nanotubes on adipose-derived stem cells (ADSCs) for viability and proliferation purposes in vitro. Materials and Methods: After chemical modification of the CNTs, the ADSCs were cultured in Dulbecco′s Modified Eagle′s. Medium (DMEM) having doses of 0.1, 1, 10, 20, 50, and 100 μg/ml of CNTs. On the third and seventh days of the experiment, the cellular viability, proliferation, and stemness were determined, using the MTT, trypan Blue, and flow cytometry assays in variable CNTs dosage. Results : In doses of 0.1 and 1 μg/ml, the expression of the surface markers were similar to the control groups on day three, but decreased in higher dosages on day seven. The viability of both groups was the same on day three, but in comparison to the control groups, was found to decrease in the higher dosages on day seven. Conclusion: The effect of CNTs on the viability and proliferation of ADSCs is a function of time and the doses used. Through further investigation by using these particles, we expect that we should be able to increase the viability and proliferation of ADSCs

Chondrogenesis of human adipose-derived mesenchymal stromal cells on the devitalized costal cartilage matrix/poly(vinyl alcohol)/fibrin hybrid scaffolds

Porous scaffolds derived from native cartilage matrix along with autologous cells could be an effective tool for cartilage tissue engineering (CTE). Recently, it was shown that scaffolds based on cartilage extra cellular matrix (ECM) can induce chondrogenesis of human adipose-derived mesenchymal stromal cells (ASCs) without using exogenous growth factors. However, lack of mechanical properties, rapid biodegradation, and contraction of these scaffolds in culture limit further applications. The present study investigated the fabrication of novel scaffolds based on devitalized costal cartilage matrix (DCM) and poly vinyl alcohol (PVA), using genipin as a natural crosslinker. For this purpose, PVA was modified to expose amine groups (PVA-A), which crosslinked with DCM powder via the lowest genipin percentage of 0.04 (wt/wt). The crosslinked scaffolds were characterized by different techniques including porosity percentage, pore size, mechanical properties, crosslinking density, and swelling. ASCs were seeded on the scaffolds using fibrin hydrogel. Gene expression measurements, biochemical assays and histological staining confirmed that ASC-seeded constructs cultured in the chondrogenic medium can express cartilage-specific genes and synthesize cartilage-related macromolecules. In the presence of TGF-β3 the constructs exhibited significant expression of these markers compared to the control medium. These findings suggest that genipin-crosslinked DCM-PVA-A/ fibrin can be considered as an appealing hybrid scaffold for CTE applications. © 2019 Elsevier Lt