Polymer vesicles prepared from the (l-phenylalanine ethyl ester)-modified hyaluronic acid

• Preparation of amphiphilic l-phenylalanine ethyl ester-modified hyaluronic acid.
• Self-assembly of amphiphilic polymer into vesicles.
• The size and wall thickness of the vesicles depend on the modification degree.

In recent years, polymer vesicles prepared by self-assembly techniques have attracted increasing scientific interest because of their numerous extensive applications in drug release, nano-reactors and catalysis. In this work, hyaluronic acid (HA) was hydrophobically modified by l-phenylalanine ethyl ester (l-Phe) via amidation reaction between the carboxylic group of HA and the amine group of l-Phe. The amphiphilic polymers could self-assemble into nanoparticles of vesicle structure. The size and wall thickness of the vesicles were dependent on the modification degree of l-Phe. The results showed that with the increase of the modification degree of l-Phe, the size of the vesicles gradually decreased and the wall thickness of the vesicles gradually increased. Morphologies of the vesicles were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM).