Importance of the free amine groups in acellular scaffold during tissue repairing or regeneration process

In addition to serve as a physical scaffold, acellular scaffold should be involved in tissue repair processes such as hemostasis, inflammation, proliferation, and remodeling/regeneration as a bioactive material. The biological activities of acellular scaffold related to free amine groups may have a great influence on tissue repairing process after in situ implantation. In order to investigate the role of free amine groups in acellular scaffold on tissue repairing/regeneration process, the amine-blocked acellular scaffolds and amine-unblocked acellular scaffolds were prepared by using bovine pericardia. The scaffolds were in situ implanted in a dog model. The in vitro and in vivo experiment results showed that free amine groups in acellular scaffolds were indispensable for the biological activities of acellular scaffolds. Free amine groups of the acellular scaffold directly or indirectly took part in tissue repairing process including integration of acellular scaffold with the damaged tissue and the remolding process of the damaged tissue. Lack of the free amine groups made the acellular scaffolds difficult to integrate with the damaged tissue and impeded extracellular matrix dynamic process, which made the tissue remolding/regeneration process impossible.