Collagen

The amino acid sequence of the primary structure is mainly a repeating motif with glycine in every third position with proline or 4-hydroxyproline frequently preceding the glycine residue. Type I collagen is a heterotrimer composed of two α1(I) chains and one α2(I) chain, which spontaneously form a triple helix scaffold at neutral pH and 37 degrees.

Role of Type I Collagen in Cellular Function

Control of cell growth, differentiation, and apoptosis in multicellular organisms is dependent on adhesion of cells to the extracellular matrix (ECM). Given that Type I collagen is an abundant component of the ECM, cells cultured in three-dimensional (3D) collagen gels simulate the in vivo cell environment better than traditional 2D systems. This has been shown for a number of cell types including cardiac and corneal fibroblasts, hepatic stellate cells (HSCs), and neuroblastoma cells. Several diseases can affect the mechanical properties of the ECM while other disease states may be caused by changes in the density or rigidity of the ECM.

Utilization of Collagen Gels in Cell Culture

Since Type I collagen is a key determinant of tensile properties of the ECM, 3D collagen gels are useful in studies of mechano-transduction, cell signaling involving the transformation of mechanical signals into biochemical signals. 3D gels allow for the study of the effects of the mechanical properties of the ECM, such as density and rigidity, on cell development, migration, and morphology. Unlike 2D systems, 3D environments allow cell extensions to simultaneously interact with integrins on all cell surfaces, resulting in the activation of specific signaling pathways. Gel stiffness or rigidity also affects cell migration differently in 3D versus 2D environments. Furthermore, integrin-independent mechanical interactions resulting from the entanglement of matrix fibrils with cell extensions are possible in 3D systems, but not in 2D systems where the cells are attached to a flat surface.

Cell Surface Receptors for Collagen Subtypes

Different collagen subtypes are recognized by a structurally and functionally diverse group of cell surface receptors, which recognize the collagen triple helix. The best-known collagen receptors are the integrins α1β1 and α2β1. α1β1 is the major integrin on smooth muscle cells, while α2β1 is the major form on epithelial cells and platelets. Both forms are expressed on many cell types including fibroblasts, endothelial cells, osteoblasts, chondrocytes, and lymphocytes. Some cell types may also express other collagen receptors such as glycoprotein VI (GPVI), which mediates both adhesion and signaling in platelets. Other collagen receptors include discoidin domain receptors, leukocyte-associated IG-like receptor-1, and members of the mannose receptor family.

Atelocollagen versus Telocollagen

Telocollagen (Extraction method: acid) and atelocollagen (pepsin treatment) are two forms of collagen that differ in their degree of chemical modification. Telocollagen is the native form of collagen found in the body, containing telopeptides, which are non-helical regions at both ends of the collagen molecule. These telopeptides play a role in cross-linking collagen fibers and stabilizing the collagen structure.

Atelocollagen is a modified form of collagen where the telopeptides have been removed. This removal of telopeptides makes atelocollagen more soluble and less immunogenic compared to telocollagen. Atelocollagen is often used in biomedical applications, such as tissue engineering, wound healing, and cosmetic procedures, due to its enhanced biocompatibility and ability to integrate more effectively with host tissues.

Our Atelocollagens are: PureCol, Nutragen, FibriCol, and VitroCol

Our Telocollagens are: TeloCol-3, TeloCol-6, TeloCol-10, and RatCol

Available Collagen Types for Research
In addition, to the Type I collagen (derived from bovine), the following species are currently available:
VitroCol (human), and RatCol (rat).
In the last decades additional collagen types were analyzed and became commercial available:
Collagen type III (human)
Collagen type IV (human)