Dialysis as a method of obtaining neutral collagen gels.

Collagen gels are useful materials for medicine and tissue engineering. They are generally obtained by chemical cross-linking of the protein chains. However, other kinds of interactions can also stabilize the structure. In our investigations we employed dialysis against deionised water as a method of neutralization of collagen solution. This promoted the creation of stable, flexible, transparent gel composed only of collagen and water. The FTIR-ATR spectroscopy showed that changing pH of the solution caused organization of collagen chains into triple-helical motifs similar to native protein. As a result, thermal stability of the material improved and the surface was more polar than in case of collagen film obtained from acidic solution. The freeze-drying of the gel provided the relatively stiff, porous material, which returned to its original shape after deformation. We expect that the method of obtaining neutral collagen gels can be widely applied for preparation of scaffolds for tissue engineering.