Thorac Cardiovasc Surg 2014; 62 - OP53
DOI: 10.1055/s-0034-1367130

Surface modified PTFE promotes endothelial cell adhesion and simultaneously inhibits the attachment of platelets and bacteria

M. Gabriel 1, H. Weiler 1, U. Mehlhorn 1, C.-F. Vahl 1
  • 1Universitätsmedizin Mainz, Klinik und Poliklinik für Herz-, Thorax- und Gefäßchirurgie, Mainz, Germany

Objectives: Thrombosis is one major cause of poor patency of synthetic vascular grafts. Amongst others, the latter is promoted by the absence of endothelialization. In addition, commonly used prosthetic materials - e.g. polytetrafluoroethylene (PTFE) - are prone to bacterial biofilm formation. The present study aims at the development of a PTFE-surface modification offering antifouling as well as endothelial cell-adhesive properties. Polyethyleneglycol (PEG) was used as a spacer molecule simultaneously providing antifouling effects. Additionally endothelial-cell (EC) specific adhesion peptide REDV was used for endothelialization.

Methods: PTFE was surface activated by a wet-chemical procedure, followed by direct (PTFE-REDV) or PEG-mediated (PTFE-PEG-REDV) peptide immobilization. Modified and untreated samples were seeded with ECs and monitored for a period of 2 weeks. In addition, specimen were tested with thrombocytes and Staph. aureus. Fluorescent-stained samples were analyzed using ImageJ software and results were expressed as percent coverage.

Results: REDV-conjugation with or without a PEG-spacer converts PTFE into an excellent substrate for cell-growth in sharp contrast to unmodified material. Colonization of ECs on modified substrates reached appr. 21% (PTFE-REDV) and appr. 18% coverage (PTFE-PEG-REDV) respectively after 2 weeks. Thrombocyte attachment was reduced 35-fold (PTFE-PEG-REDV) and 26-fold on PTFE-REDV. The latter result may be explained by the mere hydrophilicity of this surface. In addition, the modification largely prevented bacterial attachment.

Conclusions: Thrombogenicity and device-associated contamination can effectively be reduced by an appropriate functionalization. For vascular prosthesis, where endothelialization is desirable, the combination of cell-specific adhesiveness and antifouling properties may provide a basis for the development of novel (small-diameter) vascular grafts.

Fig. 1: PTFE-PEG-REDV