Biocompatibility and anti-calcification of a biological artery immobilized with naturally-occurring phytic acid as the crosslinking agent

The primary aim of this research was to evaluate the immobilization effects of a novel multi-functional crosslinking agent, phytic acid (PA), on decellularized porcine aorta fixation. Chemical modification was necessary before implantation to avoid the rapid degradation and immunological rejection caused by allotransplantation. To overcome deficiencies such as high cytotoxicity or serious calcification caused by traditional crosslinking agents, such as glutaraldehyde (GA), herein, a naturally extracted substance, PA, was employed for biological tissue fixation. The critical crosslinking characteristics and cytocompatibility of PA-fixed tissues were investigated. The results imply that PA-fixation not only formed effective crosslinking sites but also well preserved the original ultrastructure of the aorta, which simultaneously increased the mechanical strength and capacity of the enzymatic hydrolytic resistance. In addition, 5% PA (aqueous solution)-fixed tissues were characterized as having excellent cytocompatibility. The fixation eliminated cytotoxicity and significantly induced the proliferation, attachment and spreading of cells. In addition, it could stimulate the secretion of VEGF and ET-1 from seeded HUVECs, which is a critical feature for further angiogenesis. Its anti-calcification ability was also prominent, which is necessary in vascular repair. The present studies demonstrate that PA could be a potential biological crosslinking agent, due to its excellent crosslinking effects, resistance to enzymatic degradation, anti-calcification and cytocompatibility.