A facile strategy for promoting cell adhesion and function on three-dimensional printed hydrogels using photocurable epsilon-poly-L-lysine

Abstract

This study introduces a new persuasive strategy for promoting cell adhesion and function on three-dimensional (3D) printed hydrogels by incorporating photocurable epsilon-poly-L-lysine (EPL) as the cell adhesive molecule. Two different polymers, dextran (Dex) and EPL, were first modified using methacrylic anhydride and glycidyl methacrylate, respectively, to obtain the methacrylate-functionalized polymers: Dex-MA and EPL-MA. Subsequently, these modified polymers were formulated with poly(ethylene glycol dimethacrylate) (PEGDMA) before fabricating the 3D-printed hydrogels through digital light processing (DLP). The effects of the PEGDMA, Dex-MA, and EPL-MA ratios in the formulation on the physical properties of 3D-printed hydrogel and their biological responses were assessed. The 3D-printed specimens possessed compressive moduli in the range of 280–520 kPa. SEM/EDS analysis confirmed the presence of nitrogen in the hydrogels. The ninhydrin assay revealed that the EPL-MA content fell in the range of 0–0.15 mg/mg. All prepared hydrogels exhibited non-cytotoxic behavior toward NIH/3T3 fibroblasts. The benefit of incorporating EPL-MA and, interestingly, the stiffness of 3D-printed hydrogel on cell performance has been confirmed by various biological evaluations, including viability, adhesion, growth, and function of NIH/3T3 fibroblasts. Taken together, we have developed a rather promising strategy using photocurable epsilon-poly-L-lysine for promoting cell adhesion and functionalisation with potential for skin tissue engineering and other regenerative medicine applications.