Functional hyaluronic acid hydrogels prepared by a novel method

In this study, a novel simple method was developed to prepare functional hyaluronic acid (HA) hydrogels simultaneously containing hydrazone and disulfide bonds in their crossbridges. The HA hydrogels were formed by directly reacting 2,5-hexanedione and 3,3′-dithiodipropionate hydrazide-modified HA, and were characterized by FT–IR, SEM, TGA and mechanical tests. The results showed that the formation of HA hydrogels was a result of the reaction between ketone and hydrazide groups. The resultant HA hydrogels exhibited a porous morphology with a pore size range of 50 μm to 400 μm, and their compressive modulus and G″/G′ ratio were 18.8 ± 0.6 kPa and 0.002, respectively. Both swelling and degradation ratios gradually decreased with the increasing degree of crosslinking. However, the degree of crosslinking had a slight effect on the decomposition temperature of the HA hydrogels. It can be concluded that the simple method presented in this study is feasible to prepare HA hydrogels through hydrazone bond crosslinking by reacting diketone molecules and hydrazide-modified HA, and the HA hydrogels have potential in biomedical applications.