Hydrogel scaffolds for regenerative medicine

Some strategies in tissue engineering and regenerative medicine (TERM) rely on the use of an appropriate biomaterial to guide and foster tissue repair and regeneration. Collagen-based materials are perhaps the most widely investigated of these biomaterials because collagen is the primary structural protein responsible for tissue integrity in most tissues [1]. Collagen gels offer several advantages as a scaffolding material, including the ability to deliver a homogeneous distribution of entrapped cells into a specific geometry and excellent biocompatibility and transport properties [2]. However, collagen does have some disadvantages, including suppression of cell proliferation and protein synthesis [3, 4], issues that can limit the quality of the engineered tissue produced. An alternative biopolymer that shares similar properties to collagen is fibrin. Fibrin is a natural biopolymer involved in the wound-healing process, and it forms the provisional matrix of a clot. It rapidly polymerizes to form a biocompatible and biodegradable fibrous scaffold that promotes cell proliferation and ECM synthesis. Another attractive property of fibrin is that its precursor (fibrinogen) can be extracted from the patient’s blood, making it an autologous material. In this chapter we will review the properties of fibrin and fibrin-based engineered tissues and how these materials are being incorporated into TERM technologies.