The nativity and collagen organization differences among collagen dressings

Introduction: There is a variety of collagen-based wound dressing on the market. They vary in a multitude of ways including the source of the collagen, the addition of other ingredients and total collagen content. Another point of difference is the concept of the “native-ness”/”nativity” of the collagen. The word “native”, in the biochemical sense, tends to speak to the shape proteins take and can have consequences for functionality of the proteins. We sought to determine the nativity of 2 lines of marketed collagen-based dressing lines.

Materials & Methods: Four commercially available collagen-containing dressings were tested; two with silver and two without. The dressing pieces were sectioned in two different orientations, transverse (cross-section) and en face (looking directly into the dressing). The sections stained as previously reported (Junqueira 1979). The sections were imaged with 5 replicates each and the results among the dressings compared by ANOVA with Tukey's HSD as a post-hoc test.

Results:  One line of dressings had more dense collagen than the other, and the collagen in the more dense dressing was also more native (p<0.05).  The inclusion of silver did not affect the more dense line, but did for the other dressing (p< 0.05).  The less dense dressing also differed between en face and cross-section; indicating that the nativity can vary based on the depth within the dressing.  Finally, the transverse and en face views of the more dense dressings had highly branching structures that were visible in the en face but not the cross-section.  These structures were not seen in the less dense dressings.

Conclusions:  There are nativity and structural differences in the collagen of competing dressings.  Some dressings clearly have more native collagen than others as measured by staining, and different microscopic geometry.  The consequences of these differences is have yet to be determined and is the subject of on-going research.