The interaction between stem cells and biomaterials with nanoscale topography represents a main route in the roadmap for tissue engineering-based strategies. In this study, we explored the interface between human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and hydrogenated amorphous carbon (a-C:H) film designed with uniform, groove, or grid nanopatterns. In either case, hBM-MSCs preserved growth rate and multi-differentiation properties, suggesting that the films were biocompatible and suitable for stem cell culture. hBM-MSCs responded to different nanopattern designs with specific changes of microtubule organization. In particular, the grid pattern induced a square-localized distribution of alpha-tubulin/actin fibers, whereas the groove pattern exerted a more dynamic effect, associated with microtubule alignment and elongation.

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ABSTRACT:The effects of oxygen-based radio frequency plasma enhanced chemical vapor deposition (rf PECVD) on the surface of poly(L-lactide) (PLLA) polymers and the influence thereof on protein adsorption and on bone-cell behavior have been studied. Thin films and porous scaffolds based on PLLA polymer were developed, and the role of surface modifications were investigated extensively. PECVD surface treatments were used to alter surface functionality and modulate protein adsorption on the PLLA polymer matrix. In particular, Bovine Serum Albumine fluorescein isothiocyanate (fitc-BSA) conjugate adsorption on patterned surfaces of treated PLLA was analyzed by fluorescence microscopy. Human marrow stromal cells (MSCs) were cultured on scaffolds and cell adhesion and morphology were assessed using fluorescence microscopy. The results indicated that the PLLA surface became hydrophilic and its roughness increased with the treatment time and it had a dominant influence on the adsorption process of the protein. The outcome of the plasma treatment of various PLLA surfaces has been shown to be the up-regulator of the cell-adhesive proteins expression and consequently the improvement of cell adhesion and growth. Oxygen-treated PLLA promoted higher adhesion and proliferation of the MSCs in comparison to the untreated samples. It can be concluded that following plasma treatment, PLLA samples show enhanced affinity for osteoprogenitor cells.

Poly(L-lactide) (PLLA)/single-walled carbon nanotubes (SWNTs) nanocomposite films were produced using the solvent casting method, and morphological, thermal and mechanical properties were investigated. Biocompatibility was evaluated by using human bone cells, performing adhesion and proliferation studies. The role of single-walled nanotube incorporation and functionalization on PLLA bio-polymers was investigated. Pristine (SWNTs) and carboxylated (SWNTs-COOH) carbon nanotubes were considered in order to control the interaction between PLLA and nanotubes. SWNTs and SWNTs-COOH showed a good dispersion in the polymer matrix and improved the PLLA crystallinity. Thermal, morphological and dynamic-mechanical analyses revealed that carboxylic groups on the tube sidewalls increased compatibility between PLLA and nanostructures. Mechanical properties demonstrated an enhancement related to introduction and functionalization of carbon nanotubes. Biological investigations showed osteoblasts cultured on PLLA/SWNTs-COOH nanocomposites has higher cell adhesion and proliferation than osteoblasts cultured on PLLA and PLLA/SWNTs nanocomposites. These studies suggest that combination of biodegradable polymers and SWNTs opens a new perspective in the self-assembly of nanomaterials and nanodevices for biomedical applications with tunable properties.