Gellan Gum Methacryloyl-Based Composite Hydrogels to Promote Murine Primary Macrophage Differentiation

Injectable hydrogels made from biopolymers present promising platforms for tissue engineering and wound healing applications, particularly because of their tunable mechanical properties and the ability to support cell growth. In this work, we developed and characterized composite hydrogels composed of gellan gum methacryloyl (GMa), unmodified gellan gum (GG), and fibrin (Fib) to investigate their mechanical properties on Raw 264.7 and primary murine macrophages. The mechanical properties and porosity of the hydrogels were tailored by varying the ratio of GGMa and fibrinogen. Hydrogels with higher concentrations of fibrinogen (7-9 mg/mL) exhibited increased stiffness and enhanced porosity and maintained a high cell viability for both lineages. Immunocytochemistry confirmed that primary macrophages preserved their phenotype, expressing crucial markers (F4/80, iNOS, and arginase-1), indicating that the GMa-based hydrogels with optimized fibrinogen concentration can serve as effective scaffolds for macrophage response, promoting M1-M2 macrophage differentiation.