Photocrosslinkable graphene-enhanced biomaterial inks for improved printability and structural fidelity

Abstract

Extrusion-based three-dimensional (3D) printing requires biomaterial inks that combine suitable printability, rheological tunability and structural stability. Methacrylated gellan gum (GGMA) is a promising photocrosslinkable hydrogel, however, its relatively soft network can limit the structural robustness of printed constructs. The incorporation of graphene nanosheets has emerged as an effective approach to tune the rheological behaviour and polymer-nanofiller interactions of hydrogel inks. In this study, multimaterial GGMA-graphene biomaterial inks containing 0.25%, 0.5%, and 1.0% (w/w) graphene were developed and systematically evaluated. Rheological analysis demonstrated pronounced shear-thinning behaviour, yield stress, and rapid structural recovery, with graphene concentration strongly influencing flow and viscoelastic properties. In situ photo-rheology confirmed rapid UV-induced gelation, while oscillatory measurements and swelling studies revealed concentration-dependent changes in structural stability at intermediate graphene loadings. Printability assessment showed that biomaterial ink containing 0.5% graphene achieved the best balance among the tested formulations between filament fidelity, vertical stackability, and geometric accuracy, enabling fabrication of complex 3D constructs.