Construction of varying porous structures in acellular bovine pericardia as a tissue-engineering extracellular matrix

In the study, a cell extraction process was used to remove the cellular components from bovine pericardia. Varying pore sizes and porosities of the acellular tissues were then created using acetic acid and collagenase and subsequently fixed with genipin. Biochemical analyses found that these acellular tissues with distinct porous structures consisted primarily of insoluble collagen, elastin, and tightly bound glycosaminoglycans. The thermal stability, mechanical properties, and capability against enzymatic degradation of the bovine pericardial tissue remained unaltered after cell extraction. However, following further treatment with acetic acid and collagenase, the thermal stability and capability against enzymatic degradation of the acellular tissues declined. The porous structures of the implanted samples seem to determine whether successful microvessel-ingrowth takes place. The acetic-acid- and collagenase-treated tissues, due to their high pore size and porosity, showed a large number of microvessels infiltrating into the interstices of the implanted samples. In contrast, a low density of microvessels was observed infiltrating into the acellular tissue and penetration of microvessels into the cellular tissue was never encountered.