Mimicking bone tissues having layered structures is still a significant challenge because of the lack of technologies to assemble osteoblast cell types into bone structures. One of the promising and attractive materials in biomedical and different engineering fields is graphene and graphenebased nanostructures such as graphene oxide (GO) because of their unique properties. In most studies, GO was synthesized using chemical vapor deposition method, and was coated on the substrate. In this study, we proposed a simple technique for assembly of cells that facilitates the construction of osteoblast-like structures using suspended GO synthesized by graphite powder, H 2 SO 4 , and KMnO 4 .Toxicity effects of GO on human mesenchymal stem cells (hMSCs) derived from bone marrow were analyzed. In addition to normal MSCs, toxicity effects of GO on human cancer cell line saos-2 as an abnormal cell line that possess several osteoblastic features, was examined. The attachment and expression of osteoblast cells genes were evaluated after differentiation of MSCs to osteoblast cells in presence of suspended GO by scanning electron microscopy and real time PCR. We found that the toxicity effects of GO are dose dependent and in oseogenic medium containing suspended GO the expression level of osteoblast genes osteopontin and osteocalcin and cell adhesion markers connexin were higher than control group. Interestingly, through this method GO was found to induce multilayer osteoblast cell morphology and enhance the number of cell layer. We expect that the presented method would become a highly useful approach for bone tissue engineering.

Organization (AREEO), Karaj, IranPurpose: Graphene-based nanostructures have shown some degree of stem cell protection against cell death. Acute kidney injury (AKI) is a major cause of mortality in hospitalized patients. Here, graphene oxide (GO) was used to improve the efficacy of bone marrowderived mesenchymal stem cells (MSCs) in the treatment of AKI induced by cisplatin, a chemotherapy medication used to treat a number of cancers. Materials and Methods: Cisplatin-induced AKI was modeled in male rats. Intraperitoneal injection of MSCs mixed with GO, synthesized by graphite powder, H 2 SO 4 , and KMnO 4 was administered in modeled animals. Biochemical analysis of serum and histological and immunohistochemical (IHC) staining of kidney tissue samples were determined. Results: Administration of GO nanoparticles suspended in MSCs reduced serum levels of creatinine (Cr) and blood urea nitrogen (BUN) in cisplatin-induced AKI in the experimental group compared to the control group. Histopathological evaluation also showed an improvement of morphological alterations of kidney, such as cellular proliferation, apoptosis and necrosis, cyst formation and intratubular debris in the experimental group compared to the control group. Our data revealed that GO injection alone without MSCs accelerated the improvement of the kidney injury induced by cisplatin. Conclusion: This study demonstrated that suspended GO could enhance the efficacy of stem cells in the treatment of AKI. GO alone without stem cell accelerates the improvement of cisplatin-induced AKI.

Objective: Acute liver failure (ALF) is usually associated with inflammation and oxidation of hepatocytes and has high mortality and resource costs. Although mesenchymal stem cell-conditioned medium (MSC-CM) has therapeutic effects similar to MSC transplant in treating liver failure, it may not increase survival. On the other hand, graphene-based nanostructures have been proven useful in biomedicine. In this study, we investigated whether silica magnetic graphene oxide (SMGO) improved the effects of MSC-CM in protecting hepatocytes and stimulating the regeneration of damaged liver cells. Materials and methods: To provide a rat model of ALF, male rats were injected intraperitoneally with carbon tetrachloride (CCl 4 ). The rats were randomly divided into six groups, namely control, sham, CCl 4 , MSC-CM, SMGO, and MSC-CM + SMGO. In the experimental groups, the rats received, depending on the group, 2 mL/kg body weight CCl 4 and either MSC-CM with 5 × 10 6 MSCs or 300 μg/kg body weight SMGO or both. Symptoms of ALF appeared 4 days after the injection. All groups were compared and analyzed both histologically and biochemically 4 days after the injection. Results: The results indicated that the use of SMGO enhanced the effect of MSC-CM in reducing necrosis, inflammation, aspartate transaminase, alanine aminotransferase, and alkaline phosphatase in the CCl 4 -induced liver failure of the rat model. Also, the expression of vascular endothelial growth factor and matrix metalloproteinase-9 (MMP-9) was significantly upregulated after treatment with SMGO. Conclusion: SMGO improved the hepatoprotective effects of MSC-CM on acute liver damage, probably by suppressing necrosis, apoptosis, and inflammation of hepatocytes.

No abstract

No abstract