Papers by Keyword: Cell Adhesion

Abstract: New tissue-engineered vascular prostheses of small diameter (4mm) based on biodegradable polymer backbone – poly (ε-caprolactone) (PCL) and its composition with poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV/ PCL) were created. The full cycle of surface modification of the backbone with polyvinylpyrrolidone and drugs permitted to increase significantly the atrombogenic and antimicrobial properties of prostheses and provide its effective matrix properties. Both types of the developed constructs are suitable for testing in vivo. The energy characteristics of the prosthesis surfaces at the different interfaces were determined. It was established that the value of the energy of the "polymer, saturated with octane/water" interface can be used as a parameter for predicting cell adhesion and proliferation in the case when it is difficult to determine or to distinguish the energy characteristics of the surfaces of tissue-engineered materials at the interface with air.

Abstract: Dental implants have been widely used to restore missing or damaged teeth. Peri-implantitis is one of the main causes of the implant loss. However, a consensus concerning clinically successful peri-implantitis treatment has not been reached at present. We have newly proposed a treatment method for the peri-implantitis by applying the intraoral laser ablation technique to induce a surface modification of dental implants. In the present study, we investigated the cell adhesion ability of α-tricalcium phosphate (α-TCP) films formed on titanium substrates by an Erbium-Doped:Yttrium, Aluminum, and Garnet (Er:YAG) laser deposition method. Cell adhesion was enhanced by the α-TCP films attached firmly to the substrates using the Er:YAG laser deposition method. This intraoral laser deposition technique can be used to recover the osteointegration ability which was lost by the treatment procedures for peri-implantitis.

Abstract: Surface biofunctionalization is a common strategy to improve the material-tissue interface of inert implant surfaces. In this context we coated alumina-toughened zirconia (ATZ) ceramics after titanium plasma spraying with two different porous calcium phosphate layers and subsequently functionalized the obtained surfaces either with an RGD containing cell adhesion peptide sequence or a bone morphogenetic protein (BMP)-glycosaminoglycan complex. We studied initial cell adhesion densities, integrin expression, and alkaline phosphatase activity as an osteogenic marker of the coatings in vitro in comparison to the non-functionalized ATZ ceramics to evaluate the bone ingrowth potential of these biofunctionalized implant coatings.

Abstract: The osseointegration of titanium (Ti) implants highly depends on their surface properties, including roughness, wettability and composition. Ti surfaces with micron-scale roughness have demonstrated more rapid bone apposition compared with polished ones. Besides, Ti implants with nanostructured surface also exhibit better cell adhesion and proliferation behavior. However, the optimal surface for bone regeneration is still unknown, partly due to the difficulty in fabricating surfaces with highly reproducible micron-and nanotopography. In this study, Ti implants with two hierarchies of roughness were fabricated by powder metallurgy, followed by anodization treatment to obtain self-assembled TiO₂ nanotubes on the micro-roughened surface. X-ray diffraction (XRD), scanning electron microscopy (SEM), 3D Laser Scanning Microscope (3D LSM), and fluorescence microscope were used to investigate the properties of the samples. Ra of the powder metallurgy surface was about 5 μm, while, nanotubes of around 100 nm in diameter were observed after the anodization process. Compared with the reference samples, i.e., the ones with either smooth or single-level-structure surfaces, the ones with micro-to-nanoscaled hierarchical topography exhibited lower contact angle, higher protein adsorption and significantly improved mesenchymal stem cells (MSCs) early adhesion.

Abstract: The cell toxicity, cell proliferation and cell adhesion behaviors on the micro-arc oxidized surface of the conventional and large plastic deformed pure titanium (TA2) were studied. The results show that all samples have no cell toxicity. The cell proliferation ability on the surface of the large plastic deformed pure titanium (TA2) is better than that of the conventional pure titanium (TA2). The numbers of cells adhered on micro-arc oxidized surface of the large plastic deformed of pure titanium (TA2) are more than that of conventional pure titanium (TA2). And the distribution of the cells and cell morphologies are better than that of the conventional pure titanium (TA2). Results all above show that structure refinement of large deformation of pure titanium (TA2) has more significant improvement on the cell compatibility of the micro-arc oxidized modified films.

Abstract: Novel photopolymerised composite hydrogels based on PEGDMA, maleic chitosan and maleic PVA were investigated for their suitability in bone tissue engineering applications. Initial swelling and compression studies revealed that the hydrogels permitted the retention of aqueous solution while still maintaining structural integrity. Promising cytotoxicity data was obtained during direct and indirect contact exposure of composite hydrogels to pre-osteoblast (MC3T3-E1) cells. Hybrid hydrogels displayed minimal cytotoxic properties and allow tailoring of mechanical properties by variation of the loading of the maleic component in the composite. Scanning electron microscopy and live-dead staining of composite hydrogels also revealed that maleic chitosan based gels supported the adhesion of MC3T3-E1 cells and may have potential as bone tissue engineering scaffolds.

Abstract: Poly (L-lactide-co-D/L-lactide)-based fiber meshes resembling structural features of the native extracellular matrix have been prepared by electrospinning. Subsequent coating of the electrospun fibers with an ultrathin plasma polymerized allylamine (PPAAm) layer changed the hydrophobic nature of the polylactide surface into a hydrophilic polymer network and provided positively charged amino groups on the fiber surface able to interact with negatively charged pericellular matrix components. Cell experiments in vitro using different types of human epithelial cells (gingiva, uroepithel) revealed that the PPAAm-activated surfaces promoted the occupancy of the meshes by cells accompanied by improved initial cell spreading. An in vivo study in a rat intramuscular implantation model demonstrated that the local inflammatory tissue response did not differ between PPAAm-coated and untreated polylactide meshes.

Abstract: Cholesteryl ester liquid crystal was found to be non-toxic and it was recently applied as a cell traction force sensor. The reason for the affinity of the cells to this liquid crystal is unclear and required further investigation. This paper focused on determining the surface energy of the liquid crystals. A custom built contact angle measurement system and Fox-Zisman theory was applied to determine the critical surface tension of the cholesteryl ester liquid crystal. Eight different polar probe liquids were selected to determine the contact angle of the glass slides coated with cholesteryl ester liquid crystals. We found that the critical surface tension of the liquid crystal at 37.5 mN/m characterized the surface of the liquid crystal to be moderately hydrophobic. However, as reported in our previous work that the interaction of the liquid crystal and the cell culture media could re-orientate the amphiphilic molecules of the liquid crystals leading to the formation of lyotropic layers on the bulk cholesteric phase, therefore, making the surface to be hydrophilic. This then supported the formation of the hydrophilic layers that favors cell adhesion.

Abstract: The influence of the grain size of alumina and zirconia ceramics on the spreading and adhesion of MG63 cell lines was investigated. Single-component ceramics and layered composite ceramics were prepared by electrophoretic deposition, uniaxial pressing and sintering. The grain size of zirconia was 100 nm to 2.7 μm and that of alumina was 0.5 μm to 1.5 μm. Subsequently, sample surfaces were polished and thermally etched. Biological tests of adhesion (0.5 to 8 h) were used to evaluate the influence of grain size on biological response. The highest cell spreading was obtained for ZrO₂ ceramics with an average grain size of 100 and 120 nm. The cell selection was observed on layered ZrO₂/Al₂O₃ composites. The cells predominantly adhered to ZrO₂ layers. The results showed a positive influence of nanostructured ceramic surfaces on biological behaviour of MG63 cells.

Abstract: We provide here a simplified mechanochemical model to describe the role of substrate stiffness in mediating the chemical reactions between integrins on cell membrane and ligands immobilized on the substrate. By taking into account the energy input for integrin activation on a compliant substrate, Our simulation shows that integrin activation and the downstream integrin clustering can be regulated by substrate stiffness in a value-dependent manner, which is consistent with previous experimental studies.