Adhesion Of Human Osteoblast-like Cells Research Articles

Fabrication of a thick three-dimensional scaffold with an open cellular-like structure using airbrushing and thermal cross-linking of molded short nanofibers

Nanoscale fibers mimicking the extracellular matrix of natural tissue can be produced by conventional electrospinning, but this approach results in two-dimensional thin dense fibrous mats which can hinder effective cell infiltration. The aim of the present study was to design a thick, three-dimensional (3D) cylindrical scaffold with an open pore structure assembled from short polycaprolactone (PCL) fibers using a facile airbrushing approach. In addition, magnesium particles were incorporated into the PCL solution to both enhance the mechanical properties of the scaffold and stimulate cellular activity following cell seeding. Separated short composite airbrushed fibers were assembled into a 3D cylindrical structure by cold-press molding and thermal cross-linking. The microstructure, chemical composition, porosity and thermal properties were subsequently investigated, along with changes in mechanical performance following immersion in PBS for 60 d. The results showed that the assembled 3D fibrous 10 mm thick cylindrical matrix had an interconnected fibrous network structure with 31.5%–60% porosity. Encapsulation of the Mg particles into the 3D assembled fibrous scaffold enhanced the mechanical properties of the plain PCL scaffolds. The results also demonstrated controlled release of Mg ions into the PBS media for up to 60 d, as evaluated by changes in Mg ion concentration and pH of the media. In addition, the 3D fibrous assembled matrix was shown to support human osteoblast-like cell adhesion, proliferation and penetration. The results suggest that this novel fabrication method of biodegradable thick 3D scaffolds with an open pore structure is promising for the production of a new generation of 3D scaffolds for tissue regeneration applications.

Modification of in vitro degradation behavior of pure iron with ultrasonication treatment: Comparison of two different pseudo-physiological solutions

An ultrasonication treatment is developed as an external method to control the degradation behavior of pure iron. Immersion tests (weight loss measurements) and electrochemical measurements were conducted in two different pseudo-physiological solutions, simulated body fluid (SBF) and Dulbecco's modified Eagle medium (DMEM) solution. By the comparison study in these two different solutions, more information and the mechanism of the degradation process can be revealed. Degradation morphologies (with and without ultrasonication treatment) were observed by scanning electron microscope (SEM), and degradation products on the surface were characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Moreover, the biocompatibility of iron surfaces after being ultrasonicated was evaluated. Ultrasonication was found to accelerate the degradation rate in DMEM, while it makes no difference in SBF solution; the origin of this different behavior is investigated and discussed. The parameters of the ultrasonication treatment, intensity and frequency, show an influence on the degradation rate. No adverse effects on the proliferation and adhesion of human osteoblast-like cells (MG-63) are observed on surfaces after ultrasonication treatment, as compared to bare iron. Based on these results, ultrasonication treatment is considered to have high potential to control the biodegradation behavior of iron-based materials in an external and flexible manner.

Hydrogel/fiber conductive scaffold for bone tissue engineering.

Hydrogel/fiber composites have emerged as compelling scaffolds for regeneration purposes. Any biorelated modification or feature may endow more regenerative functionality to these composites. In the present study, a hydrogel/fiber scaffold possessing electrical conductivity in both phases, hydrogel and fiber, has been prepared and evaluated. Fiber component possessed electrical conductivity due to the presence of polyaniline (PANi) and hydrogel fraction thanks to the presence of graphene nanoparticles. PANi based fibers were processed through electrospinning and transformed into a three-dimensional structure through ultrasonication. The hydrogel precursor solution composed of oxidized polysaccharides, gelatin and graphene with predesigned ratio was added to fibers and left to gel. The results of assessments on pristine hydrogel and hydrogel/fiber denoted that inclusion of conducting fibers into hydrogel increased elastic modulus, roughness and electrical conductivity, whereas decreased hydrophilicity. Moreover, the results showed that hydrogel/fiber composite better supported human osteoblast-like cell adhesion, proliferation, and morphology comparing hydrogel alone. In a nutshell, the presence of gel/fiber architecture along with electrical conductivity may lead the scaffold to be very promising for bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 718-724, 2018.

Adhesion of Human Osteoblast-like Cells (Saos-2 cells) on Micro/nanopatterned Structures Sputter-Coated with Titanium

Adhesion of Human Osteoblast-like Cells (Saos-2 cells) on Micro/nanopatterned Structures Sputter-Coated with Titanium

Adhesion and proliferation of human osteoblast-like cells on different biodegradable implant materials used for graft fixation in ACL-reconstruction

This study investigates the adhesion and proliferation behaviour of human osteoblast-like cells over time when incubated on surfaces of biodegradable screws and pins used for graft fixation in ACL reconstruction. 2 mm-sized-wedges of four bioresorbable implants [1. poly-L-lactide acid (PLLA) screw, 2. PLLA/β-tricalciumphosphate (PLLA/TCP) (70 %/30 %) screw, 3. poly-L-lactide-co-glycolic acid/β-tricalciumphosphate (PLGA/TCP) (70 %/30 %) screw and 4. PLLA pin] were incubated with human osteoblast-like cells. All probes were evaluated after 3,7,14 and 21 days by cell number count, determination of cell proliferation, observation of cell adhesion of human osteoblast-like cells under an environmental scanning electron microscope (ESEM), and by a live-dead assay. Cell numbers were lower at all stages in both PLLA groups compared to the composite materials (PLLA/TCP and PLGA/TCP). A significant difference in cell proliferation was found after 21 days. The cells on both composite screws (PLLA/TCP and PLGA/TCP) maintained more contact points with the screw surface compared to the cells on PLLA screws under ESEM. No cytotoxicity could be observed in the live-dead assay. Mainly, β-TCP as part of a composite implant seems to offer good ultrastructural properties for cell adhesion according to our in vitro study. Cell numbers seem to be influenced by the degradation behaviour with higher cell numbers in the composite groups.

Reinforced Portland cement porous scaffolds for load‐bearing bone tissue engineering applications

Modified Portland cement porous scaffolds with suitable characteristics for load-bearing bone tissue engineering applications were manufactured by combining the particulate leaching and foaming methods. Non-crosslinked polydimethylsiloxane was evaluated as a potential reinforcing material. The scaffolds presented average porosities between 70 and 80% with mean pore sizes ranging from 300 μm up to 5.0 mm. Non-reinforced scaffolds presented compressive strengths and elastic modulus values of 2.6 and 245 MPa, respectively, whereas reinforced scaffolds exhibited 4.2 and 443 MPa, respectively, an increase of ∼62 and 80%. Portland cement scaffolds supported human osteoblast-like cell adhesion, spreading, and propagation (t = 1-28 days). Cell metabolism and alkaline phosphatase activity were found to be enhanced at longer culture intervals (t ≥ 14 days). These results suggest the possibility of obtaining strong and biocompatible scaffolds for bone repair applications from inexpensive, yet technologically advanced materials such as Portland cement.

Adhesion of human osteoblast-like cells (Saos-2) to carbon nanotube sheets

Carbon nanotubes (CNTs) exhibit excellent cell proliferation properties, which can serve as a scaffold for cell culturing. However, there are only a few reports on adhesion of osteoblast-like cells to a CNT sheet. In this study, we investigated adhesion of osteoblast-like cells to single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) sheets and compared these adhesions with that on a cell culture polystyrene dish by using a cell adhesion test and a scanning electron microscope. The MWNT sheets exhibited faster adhesion of cells at an initial stage than SWNT sheets and cell culture polystyrene dish. The number of attached cells on the MWNT sheets seemed to be greater than on SWNT sheets and cell culture polystyrene. Moreover, the MWNT sheets exhibited both high speed and good capacity for cell adhesion. However, the surface of the MWNT sheets was such that it facilitated cell adherence but hindered the spreading of the attached cells. Interestingly, cell adhesion to CNT sheets was significantly influenced by pre-coating with serum. These results indicate that CNT sheets would play an important role in adsorption of serum proteins, which would consequently facilitate cell adhesion, and that the MWNT sheets have a high cell adhesiveness.

The effects of silicate ions on human osteoblast adhesion, proliferation, and differentiation

Silicon has been shown to have important effects on skeletal development and repair, and soluble silicate ions have been found to stimulate the expression of type-I collagen in osteoblast-like cell cultures. Furthermore, silicon has been incorporated into the hydroxyapatite lattice and enhanced metabolic activity of human osteosarcoma cells was observed when cells were cultured on this material. In vivo assessments have demonstrated enhanced bioactivity of silicon-substituted hydroxyapatite (Si-HA) over pure HA. However, detailed mechanisms for the stimulative effects of Si-HA have not been described. In this study, we found that silicon substitution into hydroxyapatite affects the adhesion of human osteoblast-like cells (HOBs) in culture, with 0.8 wt % silicon substitution being optimal. In addition, metabolic activity and proliferation of HOBs were increased by supplementation of the growth medium with 30 microM silicon. It was determined that this response may depend on the proportion of cells at different stages of differentiation within the cultures.

Human osteoblast-like cell adhesion on titanium substrates covalently functionalized with synthetic peptides

Biomaterials to be used for the production of endosseous devices in dental, orthopedic and maxillo-facial applications, might be designed to support, guide and enhance osteoblast adhesion. Cell recruitment onto biomaterial surface is a fundamental step within the complex process responsible for implant osseointegration; this process involves several proteins from the extra cellular matrix (ECM), cytoskeleton and cell membrane. A new strategy to improve endosseous implant integration is based on preparing biomimetic surfaces able to present adhesive factors to cells. Osteoblast adhesion takes place by at least two different mechanisms: the most investigated one implies the interaction with RGD sequences via cell-membrane integrin receptors; a further mechanism concerns the interaction between cell-membrane heparan sulfate proteoglycans and heparin-binding sites of ECM proteins. In the present study two different biomimetic surfaces were obtained by covalently grafting two adhesive peptides on oxidized titanium substrates after silanization: an RGD-containing peptide and a peptide mapped on human vitronectin. The two sequences are known to act via different adhesive mechanisms. The amount of human osteoblasts adhered onto peptide-enriched or not enriched titanium oxidized surfaces and the strength of cell binding were estimated, thus comparing the capacity of the bioactive substrates in promoting cell adhesion.

Evaluation of human osteoblast-like cell adhesion strength on Ti substrates functionalized by bioactive peptide grafting

Evaluation of human osteoblast-like cell adhesion strength on Ti substrates functionalized by bioactive peptide grafting

Integrin Subunits Responsible for Adhesion of Human Osteoblast-like Cells to Biomimetic Peptide Surfaces

We have identified the integrin subunits responsible for the initial adhesion of human osteoblast-like cells to peptide-modified surfaces. Biomimetic peptide surfaces containing homogenous RGD (Arg-Gly-Asp), homogenous FHRRIKA (Phe-His-Arg-Arg-Ile-Lys-Ala), and a mixed ratio of FHRRIKA:RGD (25:75) were used to assess integrin-mediated adhesion. The RGD and FHRRIKA peptides were selected from the cell-binding and putative heparin-binding domains of bone sialoprotein. A panel of monoclonal antibodies against human alpha1, alpha2, alpha3, alpha4, alpha5, beta1, alpha(v), and alpha(v)beta3 was used to identify the subunits most dominant in mediating short-term (10 or 30 minutes) and long-term (4 hours) cell adhesion to the peptide surfaces. Anti-alpha2, anti-beta1, and anti-alpha(v) significantly (p < 0.05) diminished cell attachment to homogenous RGD surfaces following 30 minutes of incubation. After 4 hours of incubation on RGD-grafted surfaces, immunostaining of these integrin subunits revealed discrete localization of the alpha(v) subunit at the periphery of the cell (similar to focal contact points), whereas the alpha2 and beta1 subunits stained very diffusely throughout the cell. A radial-flow apparatus was used to determine the effect of anti-integrin antibodies on strength of cell detachment following 10 minutes of incubation on peptide-grafted surfaces. The strength of detachment from surfaces containing RGD was significantly reduced (p < 0.05) in the presence of anti-alpha2, anti-alpha(v), or anti-beta1 compared with controls (presence of preimmune mouse IgG). None of the antibodies significantly influenced cell attachment to homogenous FHRRIKA-grafted surfaces. These results demonstrate that initial (30 minutes) attachment of human osteoblast-like cells to homogenous RGD surfaces was mediated by the collagen receptor alpha2beta1 and the vitronectin receptor alpha(v)beta3, whereas only the vitronectin receptor governed longer term (longer than 30 minutes) adhesion (localization to focal contacts). The importance of distinct integrins in mediating the attachment of bone cells to RGD-immobilized surfaces indicates a strategy for engineering orthopaedic implants with a built-in surface specificity for cell adhesion.

Integrin subunits responsible for adhesion of human osteoblast-like cells to biomimetic peptide surfaces.

We have identified the integrin subunits responsible for the initial adhesion of human osteoblast-like cells to peptide-modified surfaces. Biomimetic peptide surfaces containing homogenous RGD (Arg-Gly-Asp), homogenous FHRRIKA (Phe-His-Arg-Arg-Ile-Lys-Ala), and a mixed ratio of FHRRIKA:RGD (25:75) were used to assess integrin-mediated adhesion. The RGD and FHRRIKA peptides were selected from the cell-binding and putative heparin-binding domains of bone sialoprotein. A panel of monoclonal antibodies against human alpha1, alpha2, alpha3, alpha4, alpha5, beta1, alpha(v), and alpha(v)beta3 was used to identify the subunits most dominant in mediating short-term (10 or 30 minutes) and long-term (4 hours) cell adhesion to the peptide surfaces. Anti-alpha2, anti-beta1, and anti-alpha(v) significantly (p < 0.05) diminished cell attachment to homogenous RGD surfaces following 30 minutes of incubation. After 4 hours of incubation on RGD-grafted surfaces, immunostaining of these integrin subunits revealed discrete localization of the alpha(v) subunit at the periphery of the cell (similar to focal contact points), whereas the alpha2 and beta1 subunits stained very diffusely throughout the cell. A radial-flow apparatus was used to determine the effect of anti-integrin antibodies on strength of cell detachment following 10 minutes of incubation on peptide-grafted surfaces. The strength of detachment from surfaces containing RGD was significantly reduced (p < 0.05) in the presence of anti-alpha2, anti-alpha(v), or anti-beta1 compared with controls (presence of preimmune mouse IgG). None of the antibodies significantly influenced cell attachment to homogenous FHRRIKA-grafted surfaces. These results demonstrate that initial (30 minutes) attachment of human osteoblast-like cells to homogenous RGD surfaces was mediated by the collagen receptor alpha2beta1 and the vitronectin receptor alpha(v)beta3, whereas only the vitronectin receptor governed longer term (longer than 30 minutes) adhesion (localization to focal contacts). The importance of distinct integrins in mediating the attachment of bone cells to RGD-immobilized surfaces indicates a strategy for engineering orthopaedic implants with a built-in surface specificity for cell adhesion.