Toward modulating the architecture of hydrogel scaffolds: curtains versus channels.

The design, development and evaluation of biomaterials that can sustain life or restore a certain body function, is a very important and rapidly expanding field in materials science. A key issue in the development of biomaterials is the design of a material that mimics the natural environment of cells. In the present work, we have therefore developed hydrogel materials that contain both a protein (gelatin) and a glycosaminoglycan (chondroitin sulphate) component. To enable a permanent crosslinking, gelatin and chondroitin sulphate were first chemically modified using methacrylic anhydride. Hydrogels containing modified gelatin (gel-MOD) and/or chondroitin sulphate (CS-MOD) were cryogenically treated as optimised earlier for gel-MOD based hydrogels (Van Vlierberghe et al., Biomacromolecules 8:331-337, 2007). The cryogenic treatment leads to tubular pores for gel-MOD based systems. For CS-MOD based hydrogels and hydrogels containing both gel-MOD and CS-MOD, a curtain-like architecture (i.e. parallel plates) was observed, depending on the applied CS-MOD concentration. In our opinion, this is the first paper in which such well-defined scaffold architectures have been obtained without using rapid prototyping techniques.