Injectable poloxamer/graphene oxide hydrogels with well-controlled mechanical and rheological properties

Although significant progress has been made in the design and application of injectable hydrogels for biomedical applications, concurrent control of rheological and mechanical properties of injectable hydrogels has remained as an open challenge to the researchers. In this work, we introduce and put into practice a photo-curable poloxamer (also known as Pluronic)/graphene oxide (Plu/GO) injectable hydrogel with well-controlled rheological and mechanical properties. Acrylate group was anchored to hydrogel structure to endow photo-crosslinking ability through decelerating degradation rate of poloxamer hydrogels after injection. It was found that the modified Plu remains stable in biological media for a long-term period without significant weight loss. Rheological properties of hydrogels were also carried out as essential prerequisite for an ideal injectability via frequency sweep, flow curve, recovery, and yield stress before and after modification, signifying shear-thinning behavior of Plu/GO hydrogels with high recoverability. The viscosity of shear-thinning-like hydrogels dropped at higher shear stress, which facilitated injection process. Moreover, mechanical behavior of Plu was optimized by manipulating the content of Plu, degree of modification with reactive precursor, curing, and particularly incorporation of GO without deteriorating effects on rheological behavior of Plu.