Hydrogels for tissue engineering

Abstract

Today's tissue engineering approaches rely on two different types of polymeric cell carriers. First, there are the well-established solid scaffolds, such as poly(α-hydroxy esters), which are generally based on lipophilic but hydrolytically degradable polymers that were originally designed as degradable sutures or drug-releasing matrix materials. Alternatively, new and promising strategies rely on hydrophilic polymer networks; these are based on hydrogels, which are also degradable polymers. Hydrophilic polymer network systems are suitable for many of the soft tissue engineering applications that do not require the strong mechanical support of solid scaffolds, but rather a flexible material that mimics the extracellular matrix (ECM). Highly hydrated hydrophilic polymer networks contain pores and void space between the polymer chains (Fig. 37.1); this provides many advantages over the common solid scaffold materials, including an enhanced supply of nutrients and oxygen for the cells. Pores within the network provide room for cells, and after proliferation and expansion, for the newly formed tissue. Their formation can be controlled using chemical modifications of the hydrogel network. © 2009 Springer Berlin Heidelberg.