Protein- and homo poly(amino acid)-based hydrogels with super-swelling properties

The use of super-swelling polymers is steadily increasing and the applications in industry are continuing to grow. With the authorization of the superabsorbents in food packaging by the Food and Drug Administration recently, demand may soon take off in the market. However, the increase in prices of petroleum products in recent years may be a drawback for these acrylic-based materials. Thus, there is now a need to develop natural-based super-swelling hydrogels which are more economical and environment friendly. In addition, the super-swelling gels are promising novel functions in the biomedical and pharmaceutical applications. This review is aimed to highlight research and trends in protein- and homo poly(amino acid)-based super-swelling hydrogels. Thus, the proteinaceous hydrogels, including chemically modified soy-, fish- and collagen-based proteins, are discussed. The protein-polysaccharicle, protein-synthetics, and the inorganic composites are also investigated as hybrid materials. Finally, the super-swelling hydrogels based on homo polypeptides, i.e. poly(aspartic acid), poly(glutamic acid), and poly(epsilon-L-lysine) are reviewed. Copyright (C) 2009 John Wiley & Sons, Ltd.