Graphene oxide modified sodium alginate/polyethylene glycol phase change material hydrogel scaffold composite with photothermal temperature control for potential bone tissue regeneration

The challenge of precisely regulating temperature during the photo-thermal bone promotion remains unresolved. Phase change material (PCM), capable of undergoing a phase transition at a specific temperature, offers a solution by photothermal temperature regulation through the storage and release of heat. This study incorporated biocompatible polyethylene glycol (PEG) with specific phase transition points as PCM. A phase change hydrogel scaffold was then synthesized through semi-crosslinking PEG with calcium-ion-chelated sodium alginate (SA) acting as the structural framework. Additionally, the newly developed graphene oxide (GO) modified composite scaffolds (GO-PHSC), featuring 0.5 wt% GO, not only demonstrated outstanding photothermal conversion efficiency and an optimal phase change temperature (42.2 °C) but also exhibited desirable values for latent enthalpy (100 J/g) and latent heat recovered (LHR) (93.3%). Moreover, the form-stability test demonstrated the PCM scaffolds' exceptional resistance to leakage and maintenance of shape stability even at elevated temperatures (70 °C). Beyond achieving passive temperature control in photothermal therapy, experimental findings highlighted that the phase change hydrogel, incorporating calcium ions and GO, met various requirements such as physicochemical properties, microstructure, mechanics, mineralization, biocompatibility, and cell affinity. These collective attributes suggest that GO-PHSC emerges as a promising scaffold composite candidate for temperature-controlled photothermal therapy in bone regeneration.