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In vitro bioactivity of MOEP grafted ePTFE membranes for craniofacial applications

Paper ID Volume ID Publish Year Pages File Format Full-Text
11870 764 2005 10 PDF Available
In vitro bioactivity of MOEP grafted ePTFE membranes for craniofacial applications

The bioactivity of three methacryloyloxyethyl phosphate (MOEP) grafted expanded polytetrafluoroethylene (ePTFE) membranes with varying surface coverage as well as unmodified ePTFE was investigated through a series of in vitro tests: calcium phosphate (CaP) growth in simulated body fluid (SBF), serum protein adsorption, and a morphology and attachment study of human osteoblast-like SaOS-2 cells. The graft copolymers were prepared by means of gamma irradiation induced grafting and displayed various surface morphologies and wettabilities depending on the grafting conditions used. Unmodified ePTFE did not induce nucleation of CaP minerals, whereas all the grafted membranes revealed the growth of CaP minerals after 7 days immersion in SBF. The sample with lowest surface grafting yield (24% coverage), a smooth graft morphology and relatively high hydrophobicity (θadv=120°θadv=120°, θrec=80°θrec=80°) showed carbonated hydroxyapatite growth covering the surface. On the other hand, the samples with high surface grafting yield (76% and 100%), a globular graft morphology and hydrophilic surfaces (θadv=60°θadv=60° and 80°, θrec=25°θrec=25° and 15°, respectively) exhibited irregular growth of non-apatitic CaP minerals. Irreversibly adsorbed protein measured after a 1 h immersion in serum solution was quantified by the amount of nitrogen on the surface using XPS, as well as by weight increase. All grafted membranes adsorbed 3–6 times more protein than the unmodified membrane. The sample with the highest surface coverage adsorbed the most protein. Osteoblast-like SaOS-2 cells cultured for 3 h revealed significantly higher levels of cell attachment on all grafted membranes compared to unmodified ePTFE. Although the morphology of the cells was heterogeneous, in general, the higher grafted surfaces showed a much better cell morphology than both the low surface-grafted and the control unmodified sample.The suite of in vitro tests confirms that a judicious choice of grafted monomer such as the phosphate-containing methacrylate monomer (MOEP) significantly improves the bioactivity of ePTFE in vitro.

Surface modification; Simulated body fluid; Protein adsorption; Osteoblast SaOS-2 cell attachment; FTIR spectroscopy
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In vitro bioactivity of MOEP grafted ePTFE membranes for craniofacial applications
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 26, Issue 26, September 2005, Pages 5303–5312
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Physical Sciences and Engineering Chemical Engineering Bioengineering