These dressing are specifically designed aid the body's natural healing processes and usually use sources of collagen derived from porcine, bovine, equine, or avian sources, which are combined with another agent, such as a gel, paste or polymer, to form a dressing. They are available in a variety of formats:
- Amorphous gels/pastes
- Gel-impregnated dressings
- ‘Rope’-type dressings for filling undermining or cavity wounds.
Some collagen dressings may also have adhesive borders
Collagen is a structural protein found throughout the human body, but is particularly common in connective tissue. Over 20 types have been discovered, although the main ones are type I, II and III, which comprise the majority of the body's collagen — types I and III are integral to wound healing. The application of these proteins to a healing wound helps to prevent the body's own collagen from degrading and provides the biological building materials needed for repair. Collagen has an important role in healing as it pulls cells such as fibroblasts and keratinocytes into the wound, which in turn aids healing processes such as debridement, epithelialisation and angiogenesis.
The collagen in a particular dressing may vary in concentration and type — for example some dressings are comprised of native collagen while others comprise denatured collagen. Other ingredients of the dressing, such as alginates and cellulose derivatives may be included to enhance absorbency, for example, and maintain a moist wound environment. Similarly, some collagen dressings may have antimicrobial properties.
Collagen dressings often require a secondary dressing to keep them in place.