Hyaluronic Acid Hydrogel Materials

This chapter discusses two protocols that are used throughout the remaining chapters. These protocols and experimental data comprise the early preliminary work of this dissertation. The first protocol is the synthesis of photocrosslinkable glycidyl methacrylate modified hyaluronic acid (GMHA). This derivative was synthesized by the reaction of glycidyl methacrylate with HA in a solvent mixture of water and acetone. The novelty of this protocol is that it used an organic water mixture to increase the degree of methacryloyl substitution. The second protocol is the synthesis of photocured GMHA hydrogel films. The literature describes many methods for creating films of hyaluronic acid. These methods typically consist of mixing HA with a chemical crosslinker in solution, adjusting the pH, casting the solution, and evaporating the solvent. This method has the advantage of simplicity but lacks reproducibility of film properties. To address the lack of reproducibility we developed a novel method of synthesizing photocured GMHA films. These films were prepared by mixing GMHA with a photoinitiator and casting the solution. After solvent evaporation the film was crosslinked by one minute exposure to UV light. This photocrosslinking method produced hydrogel films with a greater degree of control over the crosslinking reaction than is possible with chemical crosslinking methods. The photocured GMHA films were transparent, low swelling, and resistant to cell adhesion.