Injectable poly(oligoethylene glycol methacrylate)-based hydrogels with tunable phase transition behaviours: physicochemical and biological responses.

The potential of poly(oligoethylene glycol methacrylate) (POEGMA) hydrogels with varying thermosensitivities as soft materials for biomedical applications is demonstrated. Hydrogels are prepared from hydrazide and aldehyde functionalized POEGMA precursors, yielding POEGMA hydrogels with a volume phase transition temperature (VPTT) below (PO0), close to (PO10) and well above (PO100) physiological temperature. Hydrogels with VPTTs close to and above physiological temperature exhibit biological properties similar to those typically observed for poly(ethylene glycol) hydrogels (i.e. low protein adsorption, low cell adhesion and minimal inflammatory responses in vivo) while hydrogels with VPTTs lower than physiological temperature exhibit biological properties more analogous to poly(N-isopropylacrylamide) above its phase transition temperature (temperature-switchable cell adhesion, higher protein adsorption and somewhat more acute inflammation in vivo). As such, the use of POEGMA precursors with varying chain lengths of ethylene oxide grafts offers a versatile platform for the design of hydrogels with tunable physiological properties via simple copolymerization.