Acellular dermal matrix graft: synergistic effect of rehydration and natural crosslinking on mechanical properties

This investigation studied how the incorporation of a natural crosslinking agent, genipin (Gp), into the AlloDerm® (AD) rehydration protocol affects the biomechanical properties and the stability of the collagenous matrix. AD is a minimally processed, noncrosslinked, freeze-dried collagen-based graft. Samples were immersed in a saline solution for 5 min and then randomly assigned for further rehydration (30 min) into three groups, according to the crosslinking agent: G1-control (saline), G2-1 wt % genipin, and G3-1 wt % glutaraldehyde. Gp crosslinking for a prolonged time of 6 h (G4) was also investigated. After washing (5 min), samples were mechanically tested wet in tension. G2 demonstrated a significantly higher ultimate tensile strength (UTS) and E relative to G1. However, G3 did not show a noteworthy increase in these properties. A significant enhancement in UTS was found when Gp exposure time was increased from 30 min to 6 h. FT-IR revealed a protein backbone with no significant peak shifting for all samples due to crosslinking. However, a considerable decrease in -NH(2) peak intensity occurred due to crosslinking reactions. Additionally, DSC analyses indicated an important shift in the denaturation temperature for crosslinked samples. SEM micrographs revealed no alterations in the native fibrous morphology after crosslinking. Simultaneous genipin incorporation during the rehydration protocol of AlloDerm significantly enhances its biomechanical properties.