Biological performance of polyurethane membranes for implantable devices

Block-segmented molecular structure of polyurethanes (PUs) and their capacity to react or to blend with other molecules are advantageous characteristic that permits them to reach a wide range of properties. In this paper some new PUs with different soft segments, blended with HPC are investigated for their longtime preservation in aqueous media, in vivo biocompatibility and adaptability to the host tissue structure. The main methods used for investigation were scanning electron microscopy (SEM) and histological staining. From the analyzed samples, poly(eter)urethane structures were found to be more resistant to hydrolytic degradation allowing a better host tissue integration after subcutaneous implantation. After 30 days of implantation, all materials are well tolerated by the animal body. Moreover, material remodeling by massive cell and tissue ingrowth was observed for PU with polytetrahydrofuran (PTHF) in the soft segment. This bio-adaptability is accompanied by a greater porosity.