Montmorillonite-reinforced methacrylated collagen/methacrylated silk fibroin hydrogel-based inks: rheological and physicochemical characterization for bone scaffold applications.

Collagen is widely used in bone tissue engineering due to its biocompatibility; however, its poor mechanical properties, limited print fidelity restrict its use in extrusion-based bioprinting. Collagen methacrylate (ColMA) improves structural stability via photopolymerization but remains prone to enzymatic degradation. In this study, methacrylated silk fibroin (SFMA) and montmorillonite clay (MMT) were incorporated into ColMA-based systems to enhance mechanical performance and mimic aspects of the bone extracellular matrix. Successful methacrylation of ColMA and SFMA was confirmed by 1H NMR and TNBS assay, while FTIR analysis indicated interactions between the polymeric network and the clay phase. Rheological characterization, before and after UV exposure, revealed increased viscosity and a transition to predominantly elastic behavior after photopolymerization, indicating effective network formation. Extrusion-based 3D printing of SFMA/ColMA +3.0% MMT enabled the fabrication of porous grid structures with good shape fidelity, followed by rapid curing under UV light (365 nm, 40 s). These results demonstrate that montmorillonite-reinforced ColMA/SFMA systems are promising hydrogel-based inks for bone scaffold applications.