Chemical functionalization and stabilization of type I collagen with organic tanning agents

We investigated the interactions between selected organic tanning agents and type I fibrillar collagen as a model fibrillar substrate to enable the fast direct evaluation and validation of interpretations of tanning activity. Type I fibrillar collagen (1%) as gel was used as substrate of tanning and tannic acid, resorcinol- and melamine-formaldehyde and their combination at three concentrations as crosslinking agents (tannins). To evaluate the stability of collagen during tanning, the crosslinked gels at 2.8, 4.5 and 9.0 pHs were freeze-dried as discs which were characterized by FT-IR, shrinkage temperature, enzymatic degradation and optical microscopy, and the results were validated by statistical analyses. The best stability was given by combinations between resorcinol- and melamine-formaldehyde at isoelectric pH.