Surface modification of sodium hyaluronate with ferulic acid to enhance its application performance

Hyaluronic acid (HA) is a mucopolysaccharide alternately linked by glucuronic acid and n-acetylglucosamine, which is usually used as a moisturizer in cosmetics. In this study, HA derivative (FA-HA) was prepared by modifying sodium hyaluronate with ferulic acid (FA). The chemical and morphological structure of FA-HA were characterized by UV, FTIR, ¹H-NMR, DLS and TEM. The results showed that FA was grafted onto HA chains via ester bonds and self-assembled into nanoparticles in aqueous solution. The introduction of FA endowed the nanoparticles with antioxidant function. The FRAP value of 10 mg/mL FA-HA was 1.985 mM, and the clearance rate of O₂⁻, DPPH⁺ and ABTS⁺ could reach 83.13%, 88.86% and 99.48% respectively. Moreover, FA-HA can be used as Pickering emulsifiers to stabilize the emulsion. The results showed that the size of emulsion droplets decreased as the concentration of FA-HA increased. When the mass ratio of oil to water was 7/3, the emulsion droplets were the smallest. The addition of sodium chloride will increase the size of emulsion droplets, destroying the stability of the emulsion. In addition, FA-HA was also universal and was capable of emulsifying alkanes, esters, and natural oils, which was expected to be applied in the cosmetics and food fields.