BIOARTIFICIAL POLYMERIC MATERIALS OBTAINED FROM BLENDS OF SYNTHETIC-POLYMERS WITH FIBRIN AND COLLAGEN

A new class of biomaterials, called "bioartificial polymeric materials", was prepared blending a segmented polyurethane (PU) with fibrinogen (FBNG); and poly(acrylic acid) (PAA), poly(acrylamide) (PAAM), poly(vinyl alcohol) (PVAL), with collagen (CLG), respectively. The PU-FBNG material was processed through a spraying, phase-inversion technique to fabricate porous tubular conduits. FBNG was subsequently converted into covalently cross-linked fibrin (FBN) through the action of thrombin (Th), fibrin-stabilizing factor (FSF), and calcium ions. Differential scanning calorimetry (DSC) showed the cross-linked blend was more stable than native cross-linked FBN. Tensile behaviors of the PU-FBN materials closely matched those of a natural artery on varying the ratio PU/FBN. Implantation experiments in the rat model showed a mature internal capsule and good tissue organization of PU-FBN (50%) grafts in the regenerated arterial wall. However, 50% of FBN did not assure adequate mechanical resistance, and aneurysmal changes were seen in some grafts. DSC of CLG-based materials, processed by casting, showed that the synthetic component offered definite advantage compared to the CLG denaturation temperature, particularly noticeable for CLG-PAA and CLG-PVAL blends. Material advantages and drawbacks are discussed.