Osteogenic differentiation of mesenchymal stem cells using hybrid nanofibers with different configurations and dimensionality.

Novel, hybrid fibrinogen/polylactic acid (FBG/PLA) nanofibers with different configuration (random vs aligned) and dimensionality (2-D vs 3-D environment) were used to control the overall behavior and the osteogenic differentiation of human adipose-derived mesenchymal stem cells (ADMSCs). Aligned nanofibers in both the 2-D and 3-D configurations are proved to be favored for osteodifferentiation. Morphologically, we found that on randomly configured nanofibers, the cells developed a stellate-like morphology with multiple projections; however, time-lapse analysis showed significantly diminished cell movements. Conversely, an elongated cell shape with advanced cell spreading and extended actin cytoskeleton accompanied with significantly increased cell mobility were observed when cells attached on aligned nanofibers. Moreover, a clear tendency for higher alkaline phosphatase activity was also found on aligned fibers when ADMSCs were switched to osteogenic induction medium. The strongest accumulation of Alizarin red (AR) and von Kossa stain at 21 days of culture in osteogenic medium were found on 3-D aligned constructs while the rest showed lower and rather undistinguishable activity. Quantitative reverse transcription-polymerase chain reaction analysis for Osteopontin (OSP) and RUNX 2 generally confirmed this trend showing favorable expression of osteogenic genes activity in 3-D environment particularly in aligned configuration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2065-2074, 2017.

Comparative study of cytotoxicity of detonation nanodiamond particles with an osteosarcoma cell line and primary mesenchymal stem cells.

Recently, nanodiamonds (NDs) have attracted great interest due to their unique physical and chemical properties that could be used in various biological applications. However, depending on the origin, NDs often contain different impurities which may affect cellular functions and viability. Therefore, before their biomedical application, the cytotoxicity of newly produced NDs should be assessed. In the present study, we have evaluated cytotoxicity of four types of ND particles with two cell models: a human osteosarcoma cell line, MG-63, and primary rat mesenchymal stem cells (rMSCs). Detonation-generated nanodiamond (DND) particles were purified with different acid oxidizers and impurities' content was determined by elemental analysis. The particles size distribution was measured revealing that the DND particles have an average size in the range of 51-233 nm. Cytotoxicity was assessed by optical microscopy and proliferation assay after 72 hours exposure of the cells to nanoparticles. We observed cell-specific and material-specific toxicity for all tested particles. Primary stem cells demonstrated higher sensitivity to DND particles than osteosarcoma cells. The most toxic were the DND particles with the smallest grain size and slight content of non-diamond carbon, while DNDs with higher grain size and free from impurities had no significant influence on cell proliferation and morphology. In addition, the smaller DND particles were found to form large aggregates mainly during incubation with rMSCs. These results demonstrate the role of the purification method on the properties of DND particles and their cytotoxicity as well as the importance of cell types used for evaluation of the nanomaterials.