Abstract: To study the mechanism of tanning method of biological material on the molecular level by comparing the bovine pericardial valves by Glutaral tanning and by compound tanning with 1% cation fat. Methods: The histology, ultrastructure and mechanical tension resistance were tested. The content of calcium was detected in the bovine pericardial material by compound tanning with 1% cation fat and Glutaral tanning. The carboxyl content was determined with Fourier infrared spectrum instrument, and the bovine pericardial biovalve was tested with redo imitated accelerated weariness experiment platform. Results: Bovine pericardial valve by compound tanning with 1% cation fat showed firm structure under electron microscope in ten years. The collagenous fiber structure of the biological tissue arranged compactly and neatly, and the cell structure was intact. And calcification was not obvious. The content of calcium in the bovine pericardial biological material by compound tanning with 1% cation fat was lower than that by Glutaral tanning［(2.87±0.32)μg/mg vs (9.82±4.45) μg/mg］ (P＜0.05). The bovine pericardial biological material by the compound tanning was the most soft in the contracted temperature of 8690?℃, tension resistance of 19.925.8?Ｎ/ｍｍ2, bent resistance of 92.3112.7?Ｎ/ｍｍ2, and extending rate of 43.4%46.0%. Fourier infrared spectrum chart showed that carboxyl peak reduced obviously in the compound tanning, while biological material tanning with Glutaral still had rather a lot of carboxyls. Redo imitated accelerated weariness test showed 3.8×109 cycles in the bovine pericardial valve. By estimation, the biovalves were going to last for about ten years. Conclusion: The bovine pericardial material fatified with 1% cation fat overcomes the shortcomings of hard, fragile and the calcification due to tanning with Glutaral. It not only increases the firmness and softness of the biological tissue, but also keeps it from calcification. Therefore, the biovalve′s life span is longer.

Key words: Bioprosthesis, Glutaral, Cation exchange resins, Compound tanning