Skin, bones, tendons - collagen is the universal building block of life and the most abundant protein in the human body. Its unique properties make it an indispensable material in medicine.
Collagen is not just a simple protein but a fundamental building block of our body, responsible for the stability, elasticity, and regeneration of tissues. From skin to bones to tendons - collagen provides structure and support to our body as a scaffolding substance everywhere.
Its importance doesn't end with natural body construction. Due to its biological compatibility and versatile processing possibilities, collagen has developed into an outstanding biomaterial that is indispensable in regenerative medicine, drug delivery, and tissue engineering.
Provides framework for tissues and organs
Well-tolerated by the human body
Used in various medical treatments
At the molecular level, collagen resembles a multiply twisted rope structure. It is a triple helix consisting of three polypeptide strands twisted around each other. This unique structure is due to the protein's characteristic amino acid composition: glycine, proline and hydroxyproline are the most common building blocks and provide both stability and flexibility 6 .
The individual collagen molecules assemble into filaments, which in turn form fibrils and finally macroscopic fibers. This hierarchical construction system gives collagen its enormous tensile strength and makes it an ideal structural protein for tissues under mechanical stress 6 .
Glycine, proline, hydroxyproline sequences
Three polypeptide strands form the basic unit
Multiple helices assemble into fibrils
Fibrils bundle to form strong collagen fibers
Abnormalities in this complex molecular architecture or its organization can lead to a number of hereditary diseases. These include brittle bone disease (osteogenesis imperfecta) or Ehlers-Danlos syndrome, in which the stability of the connective tissue is severely impaired 6 .
A long-unsolved mystery of collagen research was how the often long and flexible strands are held together stably during self-organization. It wasn't until 2025 that researchers at the University of Bayreuth discovered the crucial mechanism: electrostatic forces in the form of salt bridges between certain amino acids 2 .
These salt bridges act as "electrostatic clamps" that fix already organized sections of the triple helix and allow the remaining strand regions to continue to organize. At the same time, they prevent local dissolution of already assembled collagen strands 2 .
Average of 50 salt bridges in the 28 known collagen types
The importance of this mechanism becomes particularly clear when you consider the number of these bridges: The 28 known collagen types have an average of 50 such salt bridges. Malformed collagens, on the other hand, have a drastically reduced number of these stabilizing connections, which is directly related to the severity of hereditary diseases such as brittle bone disease 2 .
The extraction of collagen for biomedical applications is a multi-stage process that varies depending on the desired properties of the end product. The process begins with animal raw materials such as skin, tendons, pericardium or blood vessels from cattle, pigs or fish 3 .
Removal of cell residues to prevent immune reactions
Mechanical pretreatment of the tissue for further processing
Dissolving in suitable solvents to create workable forms
Targeted enzymatic breakdown to control molecular size
Freeze-drying or convective drying to preserve the material
| Processing Form | Main Characteristics | Typical Applications |
|---|---|---|
| Decellularized Tissues | Preservation of natural tissue structure | Heart valves, vascular transplants |
| Solutions | Liquid, acid-soluble | Coatings, casting processes |
| Dispersions | Native state, viscous | Hydrogels, injection formulations |
| Powder | Partially denatured, thermoplastic | Injection molding, 3D printing |
| Gelatin | Partially hydrolyzed | Pharmaceutical capsules, food |
| Collagen Hydrolysates | Completely hydrolyzed | Dietary supplements, cosmetics |
The research and processing of collagen requires a special set of reagents and methods. A patent for collagen production lists a number of crucial components that are essential for the preparation and modification of collagen 8 .
| Reagent | Function in Collagen Processing |
|---|---|
| Papain & Other Proteases | Enzymatic cleavage of collagen structures |
| Sodium Metaphosphate | Cross-linking agent for improved stability |
| Sodium Borohydride | Reducing agent for stabilization |
| Methanol/Chloroform | Solvents for degreasing processes |
| Dithiothreitol | Protective agent for sensitive structures |
| Sodium Sulfide | Auxiliary in tissue dissolution |
These tools enable researchers to specifically modify the properties of collagen - for example through phosphorylation, in which phosphate groups are attached to the collagen molecule to increase its biological activity and stability 8 .
The excellent biocompatibility and controllable degradability make collagen an ideal biomaterial for numerous medical applications. Its areas of application range from simple wound dressings to complex tissue engineering constructs 6 .
In dentistry and implantology, collagen membranes are used as barriers to prevent unwanted cell types from migrating into bone defects and thus enable the regeneration of bone and periodontal tissue 6 .
In orthopedic surgery, collagen matrices loaded with bone morphogenetic proteins (BMP) serve as osteoinductors that directly stimulate bone formation without prior cartilage formation 6 .
Collagen serves as a carrier material for the controlled release of pharmaceuticals. The forms range from films to microspheres to nanoparticles:
Collagen gels and hydrogels offer the advantage that they are injectable and can be administered minimally invasively. They are used, among other things, as carriers for chondrocytes in the context of cartilage regeneration 6 .
By combining with synthetic polymers such as polyhydroxyethylmethacrylate (PHEMA), properties such as swelling behavior and mechanical strength can be specifically adjusted 6 .
| Product Form | Medical Application | Important Properties |
|---|---|---|
| Sponges | Treatment of burns, wound dressings | High absorbency, breathability |
| Films | Eye shields, drug delivery | Smooth surface, controlled release |
| Threads | Resorbable suture materials | High tensile strength, controlled degradation |
| Injection Molded Parts | Patient-specific implants | Dimensional stability, adaptability |
| Hydrogels | Cartilage regeneration, cell carriers | Injectable, cell-friendly environment |
Research on collagen-based biomaterials today focuses on the targeted functionalization of the protein. For example, methods are being developed at the Natural and Medical Sciences Institute in Reutlingen to modify collagen at the molecular level and thus optimize its properties for specific applications in regenerative medicine 5 .
For dental bone regeneration with complex architecture
Of bone replacement materials with long-term antibiotic activity
For cardiac applications with improved compatibility
A particularly innovative approach is the development of collagen inks for 3D printing, which make it possible to produce patient-specific tissue constructs with complex internal architecture 3 .
Collagen is much more than just a structural protein - it is a highly intelligent building system that has been optimized by nature over millions of years. Its hierarchical structure, its ability to self-organize and its exceptional biocompatibility make it an indispensable material in modern medicine.
Thanks to new insights into the fundamental stabilization mechanisms such as salt bridges and ongoing innovations in processing and functionalization, the importance of collagen-based biomaterials for regenerative medicine will continue to increase in the future. From wound dressings to bioartificial organs - collagen will continue to play a central role in shaping the medicine of the future.