Preparation of a hyaluronic acid hydrogel through polyion complex formation using cationic polylactide-based microspheres as a biodegradable cross-linking agent

A novel hyaluronic acid (HA)-based hydrogel was prepared through polyion complex (PIC) formation between cationic polylactide (PLA)-based microspheres (MS+) and hyaluronic acid (HA(-)) as an anionic polyelectrolyte. The MS+ and HA formed a biodegradable PIC hydrogel (HA(-)/MS+) when mixed in aqueous media. The swelling behavior and mechanical properties of the PIC hydrogel could be controlled by changing the charge ratio between HA(-) and MS+. In addition, the HA(-)/MS+ PIC hydrogel resulted in a lower inflammatory response compared with a collagen hydrogel in vivo.