Photo-crosslinkable, biomimetic, and thermo-sensitive pluronic grafted hyaluronic acid copolymers for injectable delivery of chondrocytes

Hyaluronic acid (HA) grafted with Pluronic F127 copolymer was used as biomimetic hydrogels for cell delivery. The graft copolymer was synthesized by conjugating amine end-capped Pluronic F127 to carboxylic groups of HA using coupling agents. The synthesized HA-g-Pluronic exhibited thermo-sensitive sol-gel transition behaviors over the temperature range of 20-40°C. HA-g-Pluronic copolymers with vinyl groups were photo-crosslinked to prepare more robust hydrogels for cell cultivation. For improved cellular adhesion and proliferation, cell adhesive peptide (Arg-Gly-Asp (RGD)) was additionally conjugated to the HA backbone. The resultant thermo-sensitive, photocrosslinkable, and RGD modified HA-g-Pluronic copolymers were used to encapsulate and cultivate bovine chondrocytes in vitro. A tissue containing cartilage-like components such as GAG and type II collagen was successfully produced within the hydrogels, indicating that the synthesized HA-g-Pluronic copolymers can be potentially used as an injectable cell carrier.