Cytocompatibility of two segmented biomedical polyurethanes

In this work the proliferation of mitogen-activated human T lymphocytes, and human endothelial cells (HEC) adhesion and growth have been evaluated in vitro with two segmented polyurethanes (SPUs) having different chemical structure: Pellethane 2363-80A, a poly-ether-urethane, and Corethane 55D, a polycarbonate-urethane. The effect of the two SPUs on phytohemoagglutinin (PHA)-induced T-cells proliferation was analysed by evaluating both morphological changes of the lympho-monocyte system with scanning electron microscopy (SEM), and the perturbation of cell cycle progression with a cytofluorimetric technique. Results showed that, although the PHA stimulation of T-cells cultured on Corethane was sufficient to induce entry into the cell cycle, as evidenced by an increase in RNA content, the DNA synthesis appeared similar to that of unstimulated cultures. On the other hand, there was a significant increase of the DNA and RNA content in the culture performed in the presence of Pellethane, as in the case of PHA-stimulated control cultures. Moreover, in comparison with Pellethane, a strong decrease in monocyte attachment and spreading was observed on Corethane; with lymphocytes scattered around the monocytes, and not attached to them as in the case of Pellethane. In the experiment with HEC, the cells were directly seeded on the materials, and the number of cells attached after 4 and 72 h culture was then evaluated, the former reading being a measure for cell adhesion, the latter indicating the capacity of the cells to proliferate. Although both SPUs allowed a HEC adhesion lower than the positive control, it was possible to confirm that Pellethane well supports cell proliferation, whereas Corethane is less prone to promote cell growth