Collagen/ Bio-Scaffolds

Collagen is the main structural protein in the extracellular space in various connective tissues. It constitutes about 30% of the total human body protein being found in fibrous tissues such as tendons, ligaments, blood vessels and bone, providing structural support and strength.

Collagen bio-scaffolds are used to guide and encourage tissue regeneration in sponge, thin sheets or gel form and is used for both in-vivo and in-vitro processes.

Collagen has properties useful for tissue regeneration: pore structure, permeability and stability in-vivo. Structure and pore size is very important and can have a significant effect on the growth of new tissue. When new tissue grows in the pores, the bio-scaffold degrades, leaving only healthy tissue.

Two key processes affecting pore size in bio-scaffolds are:

Freeze drying:

This process not only increases shelf life of the material, but controls pore size, which is vital for the growth of new tissue. Collagen is extremely sensitive to the cooling rate, therefore, it is important to choose a suitable cooling rate as well as a container that has an appropriate heat transfer coefficient as this can have a significant effect on properties of the final product.

The addition of an annealing step and freeze drying a material twice can also be employed to obtain the desired structure.

Crosslinking:

A crosslink is a bond that links one polymer chain to another. Precaution must be taken during the crosslinking process as a micro collapse may be generated, which specifically happens in collagen-based products when they are impregnated with other solutes then lyophilised.

Choosing the correct crosslinking agent for your specific purpose is vital, and one should be made aware that some of the agent will likely remain in the final freeze dried product.

Biopharma Group has undertaken numerous projects determining the effect of different freezing rates and the addition of an annealing step on the pore size of various collagen based products. In addition, we have developed cycles for customers, achieving collagen products with different pore sizes, and we look forward to future challenges in this field.