Collagen
Collagen is a protein with unique chemistry and specific function. In the proper form, collagen has many responsibilities in the body - such as aiding cellular activity and providing an organized matrix in skin. An understanding of collagen's chemical, physical, and biological properties will help clinicians utilize collagen technology effectively in their wound care protocols.
Collagen is a natural biomaterial present in all animals. In the proper form, collagen has biological properties which provide function and integrity to body tissues.
Collagen's Role in Healing
Collagen molecule chemistry
Collagen in the Body
- A structural protein with unique chemistry.
- Provides structure and integrity to most body tissues.
- Distribution and orientation reflects tissue function.
- Must be in the proper form to elicit biological functions.
Molecules self assemble into fibers
Collagen in the Proper Form
- Chemistry consists of helical and nonhelical domains.
- Molecules must be complete to provide appropriate biological response.
- Self-assembled molecules form fibers and aggregates.
- Intact fibers cause cell growth, activity, and migration.
- Aggregates have specific binding sites for cells and cell binding proteins in the body.
- Functional aggregates result in strong, healthy tissues
Fibers from aggregates
- Aggregates have specific binding sites for cells and cell binding proteins in the body.
- Functional aggregates result in strong, healthy tissues
Aggregates become skin tissue
Human and Bovine Collagen
- Human collagen varies because producing exact duplicates may be biologically uneconomical.
- Composition of collagen in bovine is within the rang e of variance of collagen duplicated in human tissues.
- Amino acid chain sequences are similar.
Human and Bovine Collagen
Transmission electron microscopy illustrates that the structure of bovine collagen fibrils presented in textbooks (left) closely resembles the structure of fibrils found in dressings containing collagen in the proper form ( right)
Bovine Collagen
These fibrils are 0.5 µm in diameter with repeat structural units that result in periodic striations
Collagen in Proper Form
These fibrils are 0.5 µm in diameter. Fibrils self assemble to form fibers and aggregates.
Collagen vs. Non-Collagen
Collagen has specific chemistry, fibrillar structure, and aggregate structure. In the proper form, collagen has functional and biological properties which are lacking in improper collagen and other materials.
Collagen: 20 weeks ar 20x magnification
When in the proper form, collagen is replaced by newly deposited collagen (blue) in the bodyCollagen in the Proper Form
- Contains complete molecules.
- Contains fibrils with banding pattern.
- Forms aggregates 9 with rope-like structure.
- Has structural and biological properties of native collagen
Collagen composite: 20 weeks at 20x magnification
Produces a response that is similar to non collagen materials. There is a lack of newly deposited collagen (blue) and a presence of foreign body giant cells (purple).Collagen in Improper form
- Fails to meet scientifically accepted definition of collagen.
- Has irregular structure, resembling that of n on-collagen materials.
- Exhibits biological responses that are analogous to non -collagen materials.
- Lacks functional properties of collagen
Alginate: 20 weeks at 20x magnification
Other materials can cause foreign body responsesOther Materials
- Lack biological form and function.
- Provides an artificial environment .
- These non -collagen mate rials are not natural to the human body.
Collagen Aggregates & Structure
Collagen in the proper form has an ordered structure
Proper Form
Fibers self assemble into aggregates which resemble rope-like structures
Improper Form
Soluble collagen: Lacks nonhelical domains, forms disorganized fibrils
Insoluble Collagen: No ordered structural matrix.
Other materials
Simple hydrogel: Lacks any organized structure
Glossary
- Aggregate: A mass or assemblage.
- Amino Acid: Any organic compound containing an amino and a carboxyl group.
- Alginate: A salt of alginic acid , which is extracted from marine kelp. Calcium, sodium, and ammonium alginates have been used as foam, clot, or gauze for absorbable surgical dressings.
- Collagen: The most prevalent protein in the anima l kingdom responsible for the structure and integrity of most tissues. A protein containing domains of triple-helical conformation . Characterized by repetitive Gly X-Y sequences where glycine is in every third residue, and stabilize d by praline and hydroxyproline residues. A protein that participates in formation of extra cellular aggregates which are primarily supporting elements.
- Collagen Fibrils: Delicate fibrils of collagen in connective tissue, usually cemented together in wavy bundles.
- Hydrogel: A gel that has water as its dispersion medium.
- Protein: Any of a group of com plex organic compounds which contain carbon, hydrogen, oxy gen, nitrogen, and usually sulfur, and which are widely distributed in plants and animals. Twenty different amino acids are com manly found in proteins. and each protein has a unique, genetically defined amino acid sequence which determines its specific shape and function.
