Collagen Scaffolds for Tissue Engineering
The three main components of tissue engineering applications are scaffold, cell and growth-stimulating signals. Collagen has been widely used in the clinical field due to its abundance in nature, biocompatibility, low antigenicity and biodegradability. In addition, the high tensile strength and fibril-forming ability of collagen enable it to be made into various forms such as tissue grafts, hydrogels, sponges, fibers, films, hollow spheres, and so on. The wide choice of manufacturing techniques and the excellent biological and physicochemical properties of collagen have stimulated the use of collagen scaffolds in various tissue engineering applications.
Tissue grafts
Due to its good biocompatibility, bioactivity and degradability, collagen has been widely studied as a tissue graft. For example, it can be used as bone repair material, tendon repair material, vascular stent and so on.
Self-assembled hydrogels
The fluidity of collagen hydrogels is primarily due to their high liquid phase, as well as their fast assembly time at physiological pH and temperature, making them ideal carriers for injectable systems and cellular and therapeutic/bioactive molecules.
Freeze-dried sponges
To date, many molecules and cell populations have been used to further enhance the biological activity of collagen sponges, with encouraging results in both in vitro and in vivo environments.
Self-assembled fibers
The self-assembled fibers, produced based on the principles of isoelectric focusing, have similar structure and mechanical properties to natural tissues. Even in the presence of myelin-associated glycoproteins known to inhibit neurite guidance, its anisotropic matrix has been shown to induce bidirectional growth of tendon-derived fibroblasts and bone marrow stromal cells, and to stimulate the tenogenic differentiation of bone marrow stem cells.
Collagen films and tubes
The isotropic collagen films prepared by evaporation have been widely used in the biomedicine of corneal repair due to its transparent nature and low demand for tissue mechanics.
Collagen tubes are widely used in clinic as nerve guidance conduits, showing limited myofibroblast infiltration, guiding Schwann cell migration and axon regeneration to distal targets.
Template-produced hollow spheres
Hollow collagen spheres can be prepared with sulfonated polystyrene beads as a template. Scaffolds, made from these hollow collagen spheres, have been used for gene, growth factor, and drug delivery or reactive oxygen species (ROS) scavenging.