Chapter 17 - Biological macromolecules for drug delivery in tissue engineering

Abstract

To regenerate various tissues, such as bone, cartilage, skin and nerve, biomedical scaffolds should provide biological support for neo-tissue formation and survival, as well as appropriate mechanical properties. In addition, to ensure the desired effect, the scaffold must possess the ability to be loaded with cells and growth factors specific to the affected tissue. Working inside the body or in contact with it, the polymers from which the scaffold is obtained should be biocompatible and biodegradable, thus avoiding the need for its subsequent removal by surgery. Finally, to prevent or to threat undesired effect, such as inflammation and infection, the scaffold can be loaded with various drugs. These conditions imposed on biomaterials for tissue engineering are met mainly by natural polymers (polysaccharides and proteins) and only by a limited range of synthetic polymers. Considering the mentioned constraints, the realization of a scaffold must be the result of a real engineering design activity, which takes into account, depending on its destination, the appropriate polymer to be used, the formulation methods, the ability to respond to external stimuli, and ultimately the preparation method. The literature on obtaining biomaterials with applications in tissue engineering has experienced a real explosion, especially in the last decade. As a result, this chapter proposes to review the most important categories of scaffolds such as drug-loaded electrospun fibers and drug-loaded injectable hydrogels. Although the literature revealed that a great variety of polymeric biomaterials for tissue engineering applications has been designed and tested until now, only a few systems are scaled up for use in clinical applications. Therefore it is obvious that it is imperative to amplify research in this field in order to develop clinically available devices for tissue engineering and regenerative medicine.