Controlled Release Strategies in Tissue Engineering

This chapter deals with the tissue-engineering strategies that depend heavily on the provision of bioactive signals, be they substrate-bound adhesion signals, or bound or diffusible growth factor signals. As such, controlled release technologies play an important role in the overall task of tissue engineering. Controlled release means that the drug is released from the surface or bulk of an implant slowly over long periods of time, and sometimes it means that the drug is immobilized on the surface of or throughout the material and is not released at all. The difference depends on the mode of action of the drug. In tissue engineering, one often uses biomaterial scaffolds or matrices, here using the word scaffold to refer to a macro- or microporous material used to provide a structural support and the word matrix to refer to a nanoporous continuous material for the same purpose.