Injectable PNIPAM/Hyaluronic acid hydrogels containing multipurpose modified particles for cartilage tissue engineering: Synthesis, characterization, drug release and cell culture study.

Novel injectable thermosensitive PNIPAM/hyaluronic acid hydrogels containing various amounts of chitosan-g-acrylic acid coated PLGA (ACH-PLGA) micro/nanoparticles were synthesized and designed to facilitate the regeneration of cartilage tissue. The ACH-PLGA particles were used in the hydrogels to play a triple role: first, the allyl groups on the chitosan-g-acrylic acid shell act as crosslinkers for PNIPAM and improved the mechanical properties of the hydrogel to mimic the natural cartilage tissue. Second, PLGA core acts as a carrier for the controlled release of chondrogenic small molecule melatonin.