Photopolymerized hyaluronic acid-based hydrogels and interpenetrating networks

This chapter focuses on photopolymerized hyaluronic acid-based hydrogels and interpenetrating networks. Hyaluronic acid (HA) is derivatized with methacrylic esters used for the preparation of hydrogels via photopolymerization. Poly(ethylene glycol) diacrylate (PEG-DA) with a molecular weight of 570 is also used as a comacromonomer to improve elastic modulus and swelling behavior. The hydrogels are readily degraded by hyaluronidase, and their mechanical properties can be modulated by HA molecular weight and concentration of PEG-DA. The incorporation of RGD peptides allowed modulation of the HA properties from cell non-adhesive to adhesive. Human dermal fibroblasts are cultured on the RGD, RDG, and nonfunctionalized HA hydrogels for up to 7 d, showing adhesion and proliferation only with incorporated RGD. Finally, the introduction of an RGD peptide showed dramatic changes in terms of cell adhesion and proliferation. Cells cultured on the RGD-modified hydrogel proliferated and grew to confluence, whereas cells on the RDG control hydrogel did not show any sign of spreading over long durations in culture and in the presence of serum proteins.