[Surface properties and characteristics of PU-PTHF/MDI/HPC poly(ether)urethane for cardiovascular prosthesis]

The polyurethanes are very used materials for medical devices. Their segmented block-copolymeric structures endows them a wide range of versatility in terms of tailoring their physical properties, and tissue compatibility.

A new polyether-urethane based material (PU-PTHF/MDI/HPC) was studied on bio-integration capacity in cardiovascular applications. In this respect, surface and bulk structure analysis, albumin and fibrinogen adsorption (in noncompetitive and competitive condition) and thrombogenicity have been evaluated. It was found that PU-PTHF/MDI/HPC surfaces had different roughness and bulk interconnected, well developed porous structure. As protein adsorption properties, preferential adsorption for albumin of material was observed.

Thus, 0.280 +/- 0.04 mg/cm2 and 0.260+0.01 mg/ cm2 of albumin adsorb on PU-PTHF/MDI/HPC in noncompetitive and competitive conditions, while fibrinogen adsorption was 0.044 +/- 0.02 mg/cm2 and 0.040 +/- 0.01 mg/cm2. The clot amount test experiment have shown that clot weight of control blood was 24.8 +/- 2.03 mg, the clot weight formed by polyurethane was 28.4 +/- 2.93 mg and the clot weight formed by thrombogenic positive control (collagen membrane) was 42.5 +/- 3.50 mg.

From our study we could conclude: 1--PU-PTHF/MDI/HPC polyurethane membranes have two-interface structure that could be advantageous for cavitary or tubular medical devices; 2--the protein adsorption results and clot formation test revealed a thromboresistent behavior of PU-PTHF/MDI/HPC, appropriate for cardiovascular applications.