Comparing the Extent of Collagen Nativity of Collagen Powder Dressings

-Introduction:  Collagen dressings are now a mainstay item used in the treatment of wounds.  Aside from differences in the source material, the collagen products from various vendors are also processed differently.  Native collagen is a triple helix of 3 independent protein molecules. When the triple helix is lost, the substance is then typically refered to as denatured collagen or gelatin.  A new generation of collagen-based poducts has emerged in powder fom.  This experiement sought to determine the extent to which nativity was retained by 4 commercially available collagen powders. 

-Methods:  The degree of nativity was assessed histologically using the Picrosirius Red method.  Briefly, the collagen powders were fixed 10% neutral buffered formalin.  A dense paste of the powder was then embedded, sectioned, and stained with Picrosirius Red.  Eight brightfield and phase contrast (4x, Ph2) fields of view were randomly imaged for each dressing.  The percent nativity was calculated by the area of birefringence vs the area of red staining.  ANOVA and Tukey’s post hoctest were used to discern any differences. 

-Results: There were very substantial difference among the 4 dressings (p = 1.8 x 10^-18).  Three of the four dressings were between 23 – 34% native, while the 4thdressing was between 2 – 3 times more native (83%, p = 0.001).  

-Conclusion: While the pulverisation process is expected to reduce nativity, at least one dressing still was 83% (by area) native.