Troubleshooting non-gelating collagen

15 July 2024

Collagen can fail to gelate. This may be due to a multiple of factors which are discussed in this article.

Collagen is a structural protein that is abundant in the extracellular matrix of various connective tissues in animals, including skin, bones, tendons, cartilage, and blood vessels. It is composed of three polypeptide chains wound together in a triple helix, providing tensile strength and structural integrity to tissues. There are several types of collagen, with Type I being the most common in the human body.

Collagen is widely used in cell culture for many reasons

Biocompatibility: Collagen is naturally occurring in the body, making it highly biocompatible. This reduces the risk of immune rejection and adverse reactions when used in biomedical applications.

Biodegradability: Since collagen is a protein, it can be broken down by the body’s natural processes, making it an ideal material for temporary scaffolds and implants that are designed to degrade as new tissue forms.

Cell Adhesion: Collagen provides a natural substrate for cell adhesion, growth, and differentiation. This is crucial for creating environments that mimic in vivo conditions, which is essential for accurate cell culture and tissue engineering studies.

Mechanical Properties: Collagen’s unique triple-helix structure provides excellent tensile strength and flexibility, making it suitable for applications that require materials to withstand mechanical stress, such as in tendons, ligaments, and skin.

Versatility: Collagen can be processed into various forms, including gels, sponges, films, and fibres, allowing for a wide range of applications in different research fields. This versatility makes it adaptable for specific experimental needs.

Support for Tissue Engineering: Collagen scaffolds can support the growth and differentiation of various cell types, making it a cornerstone in tissue engineering. It helps in creating three-dimensional structures that mimic the natural extracellular matrix, facilitating the development of functional tissues.

Why collagen fails to gelate

Collagen can fail to gelate due to several factors, including concentration, temperature, and pH. For stable 3D gel formation, it is essential that the collagen concentration is high enough to facilitate sufficient intermolecular interactions and network formation. Lower dilutions may be sufficient for coatings, but close to 3 mg/mL is typically recommended for gelation.

Gelation is highly temperature-sensitive, and optimal gelation generally occurs at 37 °C. Temperatures above or below this can either disrupt the non-covalent interactions necessary for gel formation or slow down/inhibit the process. The pH of the collagen solution is also critical for gelation. An optimal concentration of H+ ions helps to achieve the isoelectric point, enabling the close association of fibres and inducing gelation. This typically occurs within a slightly acidic to neutral pH range. Deviations from this range can disrupt the electrostatic interactions and hydrogen bonding essential for gel formation.

Mechanical disturbances during the gelation process can disrupt the formation of a stable gel network. Additionally, the presence and concentration of ions in the solution can significantly influence gelation, as certain ions can either stabilize or destabilize the collagen network.

Cell Guidance Systems offers a range of human-origin collagens for research.

IMAGE Collagen structure. CREDIT Nevit Dilmen Creative commons