Hydrophobic and fibrillar microporous polyetherurethane urea prosthesis: an ESCA study on the internal and external surfaces of explanted grafts

Abstract

The ESCA study gives a good qualitative and quantitative elemental analysis of internal and external surfaces of foreign materials. Microporous Hydrophobic Mitrathane® (a polyetherurethane urea) grafts were implanted as blood conduits in dogs for up to 6 month. Surface analysis of explanted grafts demonstrated the presence of different contaminants: sodium, chlorine, silicon, in patent grafts, i.e. those implanted for 1 month and less. The sulphur probably comes from the presence of proteins on the surface of the polymer and the high level of nitrogen is also protein-related. At 6 month implantation, the grafts were occluded and a decrease of proteins on the surface was observed. The values of N/C and O/C ratios are also reported. For the virgin material, these ratios correspond to the quantity of hard and soft segments; but, for the explanted grafts, these parameters are also influenced by the presence of proteins due to the Versaclean® washing which did not wash away all the proteins on the surface of the polymer. The SEM photographs showed a certain degradation of polyurethane after 6 month of implantation. However, by ESCA study, it is difficult to compare the surface of virgin and explanted grafts because it is masked by the presence of proteins.