Physical and blood contacting characteristics of propyl sulphonate grafted Biomer.

Propyl sulphonate groups were grafted on to the backbone of Biomer, a polyetherurethaneurea, in an attempt to improve its blood-contacting properties. The bulk, surface and blood-contacting properties of this series of sulphonated polymers were evaluated. Differential scanning calorimetry and dynamic mechanical analysis indicated that propyl sulphonate incorporation increased the microphase separation of the polymers. The ultimate tensile strength was also increased with sulphonation at the expense of the polymer's extensibility. Dynamic contact angle analysis showed that, in water, the sulphonated Biomer surfaces were more polar than the Biomer sample indicating the propyl sulphonate groups were enriched at the surface. Canine ex vivo blood-contacting results showed that the incorporation of propyl sulphonate groups dramatically reduced the number and activation of platelets adherent to the polymer surface. In addition, fibrinogen deposition increased with increasing sulphonate content, despite the low level of platelet activation.