Vascular endothelial cell responses to different electrically charged poly(vinylidene fluoride) supports under static and oscillating flow conditions

We investigated the effect of electrically charged surface copolymers on endothelialization of four types of poly(vinylidene fluoride) (PVDF) copolymer surface films with different electrical characteristics. PVDF films without a surface charge, with a remanent surface (5 and 7 mu C) and with piezoelectric characteristics were studied through the secretion by an endothelial cell (EC) line culture, under static and oscillating flow conditions, of prostacyclin (PG12) and thromboxane (TXA2), two metabolites which have directly opposing actions on platelet function. The surface electrical properties of PVDF are suitable for promoting cell adhesion. Secretion of thrombomodulatory mediators varied, depending on the surface electrical charge and on the molecular structure of the PVDF substrate. Under static conditions the ECs respond to the substrates by a similar increase of PG12. Under oscillating flow conditions, the ratio of PG12 to TXA2 is higher with the piezoelectric PVDF film. The piezoelectricity generated from shear stress along the entire length of the fibres may be appropriate in vivo to keep the [PG12]/[TXA2] ratio at a level which could counteract the build-up of surface deposits which could be at the origin of thrombosis. (C) 1996 Elsevier Science Limited.