|Christoph Löhlbach1, Udo Bakowsky1, Carsten Kneuer1, Thomas Graeter2, Hans Joachim Schäfers2, and Claus-Michael Lehr1
1Saarland University, Biopharmaceutics and Pharmaceutical Technology, Geb. 8.1, Im Stadtwald, D-66123 Saarbrücken, Germany, and
The replacement of blood vessels is one of the most important procedures in cardiovascular surgery. The surgical insertion of arterial implants with an inner diameter of > 6 mm is possible with good long term results, but venous and arterial implants with a narrow lumen smaller than 4 mm present current limitations. The blood coagulation cascade recognizing the synthetic surface occlude the blood vessel prosthesis after a short period. The lining of autologuos Endothelial Cells (EC) to prosthetic PTFE-Grafts has been promoted as a method of improving graft patency. Since the performance of simple Coating with Extracelluar Matrix Proteins is insufficient, the cells were washed away under perfusion, we covalently coupled a specific cell-adhesion molecule to the polymer surface. Contact angle measurements and Fourier Transform Infrared spectroscopy confirmed this chemical modification of PTFE. High resolution Atomic Force Microscopy was used to analyze surface morphology to show changes up to the level of binding molecules. Confocal Laser Scanning Microscopy demonstrated insufficient and irregular cell-lining with unmodified PTFE-grafts as well as with activated and control protein modified PTFE-grafts. Only PTFE-graft covalently modified with our specific adhesion molecules showed a regular cell-lining even under perfusion. We could show that EC adhere on formerly inert PTFE surfaces and allow a complete lining of the graft. This cell monolayer was physiological active and was able to withstand shear stress in perfusion culture.