A drug-carrying composite hydrogel with pH sensitivity for bone tissue engineering

Many tissue engineering materials have been developed in response to the need for cartilage repair surgery so far, but the complication regarding implant-induced infections remains one of the most challenging problems. Hydrogel is an excellent candidate for biomedical applications due to its biocompatibility, absorption capacity, and tunable mechanical properties. How to design the hydrogel as tissue engineering materials to achieve the task of repairing cartilage and avoiding the complication arouses wide interest. In this work, a new pHresponsive dual network hydrogel of immobilizing hydroxyapatite (HA) is synthesized to control antiinflammatory drug release. The hydroxyethyl methacrylate (HEMA) is coupled with HA, and the radical polymerization of HEMA-HA with acrylic acid (AA) is carried out in a polyvinyl alcohol (PVA) solution to form a dual-network composite hydrogel. When the mass ratio of AA to HEMA-HA is 30/1, the hydrogel shows a porous honeycomb structure and resistance to water loss. In particular, the volume of the hydrogel can well respond to the pH change in the solution. The tensile strength and elongation at break reach 333+9.32 KPa and 278 +13.89 %, respectively, exhibiting resistance to tensile fatigue. The hydrogel possesses good bioactivity. It can serve for drug delivery, and the drug release rate is 51.35+2.39 % at 48 h. The work opens a window to design specific hydrogel for tissue engineering.