Modulation of Cellular Colonization of Porous Polyurethane Scaffolds via the Control of Pore Interconnection Size and Nanoscale Surface Modifications.

Full-scale cell penetration within porous scaffolds is required to obtain functional connective tissue components in tissue engineering applications. For this aim, we produced porous polyurethane structures with well-controlled pore and interconnection sizes. Although the influence of the pore size on cellular behavior is widely studied, we focused on the impact of the size of the interconnections on the colonization by NIH 3T3 fibroblasts and Wharton's jelly-derived mesenchymal stem cells (WJMSCs). To render the material hydrophilic and allow good material wettability, we treated the material either by plasma or by polydopamine (PDA) coating. We show that cells weakly adhere on these surfaces. Keeping the average pore diameter constant at 133 μm, we compare two structures, one with LARGE (52 μm) and one with SMALL (27 μm) interconnection diameters. DNA quantification and extracellular matrix (ECM) production reveal that larger interconnections is more suitable for cells to move across the scaffold and form a three-dimensional cellular network. We argue that LARGE interconnections favor cell communication between different pores, which then favors the production of the ECM. Moreover, PDA treatment shows a truly beneficial effect on fibroblast viability and on matrix production, whereas plasma treatment shows the same effect for WJMSCs. We, therefore, claim that both pore interconnection size and surface treatment play a significant role to improve the quality of integration of tissue engineering scaffolds.journal article2019 Jun 052019 05 24importe

A new approach to graft bioactive polymer on titanium implants: Improvement of MG 63 cell differentiation onto this coating

1 - ArticleIntegration of titanium implants into bone is only passive and the resulting fixation is mainly mechanical in nature, with anchorage failure. Our objective, to increase the biointegration of the implant and the bone tissue, could be obtained by grafting a bioactive ionic polymer to the surface of the titanium by a covalent bond. In this paper, we report the grafting of an ionic polymer model poly(sodium styrene sulfonate) (polyNaSS), in a two-step reaction procedure. Treatment of the titanium surface by a mixture of sulfuric acid and hydrogen peroxide allows the formation of titanium hydroxide and titanium peroxide. In the second reaction step, heating of a metal implant, placed in a concentrated solution of sodium styrene sulfonate monomer (NaSS), induces the decomposition of titanium peroxides with the formation of radicals capable of initiating the polymerization of NaSS. Various parameters, such as temperature of polymerization and time of polymerization, were studied in order to optimize the yield of polyNaSS grafting. Colorimetry, Fourier-transformed infrared spectra recorded in an attenuated total reflection, X-ray photoelectron spectroscopy techniques and contact angle measurements were applied to characterize the surfaces. MG63 osteoblastic cell response was studied on polished, oxidized and grafted titanium samples. Cell adhesion, alkaline phosphatase activity and calcium nodules formation were significantly enhanced on grafted titanium samples compared to unmodified surfaces. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Grafting of bioactive polymers onto titanium surfaces and human osteoblasts response

1 - ArticleTitanium is widely used in orthopedic and dental implants for its excellent resistance to corrosion and its biocompatibility. In order to improve the long-term osteointegration of titanium, bioactive polymers bearing ionics groups such as sulfonates (sodium polysytrene sulfonate, poly-NaSS) are grafted by a covalent way onto titanium surface. The surface is chemically modified and then bioactive polymers are grafted by radical polymerization. The chemical composition of grafted surfaces is given by ATR/FTIR and XPS which certified the presence of sulfonate groups at the surface of grafted titanium. Quantitative grafting of polyNaSS is determined by a colorimetric method and evaluated at 5 mu g/cm(2). In vitro study is performed in order to see the effect of these bioactive polymers on the mineralization of human osteoblast (line MG63). After 28 days of cultured cells on grafted titanium surfaces and non-grafted ones, the amount of calcium onto surfaces is quantified. The results show that the mineralization of these cells is improved with the presence of polyNaSS. The amount of calcium is increased on grafted surfaces compared to non-grafted ones. Cell adhesion was evaluated. Cells were seeded onto grafted and non-grafted titanium and then subjected to detachment forces. The results show that the attachment of human osteoblasts-like cells is increased for grafted titanium with polyNaSS. A study on titanium surface grafted by polymers bearing ionics groups such as carboxylate and phosphate is in progress. (C) 2007 Elsevier Masson SAS. Tons droits reserves

Modulation of Cellular Colonization of Porous Polyurethane Scaffolds via the Control of Pore Interconnection Size and Nanoscale Surface Modifications

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