Hybrid methacrylated PCL/inulin photosensitive resins for 3D printing: a step forward in bone tissue engineering

This study addresses the need for innovative, biocompatible photopolymerizable resins for resin-based 3D printing (3DP) in bone tissue engineering (BTE). A new class of hybrid resins was developed by combining polycaprolactone trimethacrylate (PCLTMA) of two molecular weights with methacrylated inulin (INUMA) at varying concentrations. This strategy aimed to overcome the hydrophobicity and slow degradation of PCL by introducing a more hydrophilic and bioactive component, while maintaining high printability. The resins were characterized and processed into macroporous scaffolds via stereolithography (SLA). The resulting scaffolds were evaluated for dimensional accuracy, surface topography, mechanical properties, wettability, swelling, and degradation. Biological performance was assessed using human mesenchymal stem cells (hMSCs) and SAOS-2 cells, focusing on cytocompatibility, cell adhesion and osteogenic potential. Results showed that scaffold properties could be tuned by varying PCLTMA molecular weight and INUMA content. Specifically, decreasing PCLTMA molecular weight enhanced crosslinking density and mechanical strength, while increasing INUMA content improved wettability, swelling capacity, and biodegradability. All scaffolds demonstrated good cytocompatibility and supported hMSCs adhesion, confirming suitability for biomedical use. Furthermore, an optimized drug-eluting scaffold incorporating raloxifene hydrochloride (RAL) was developed, achieving uniform drug distribution and a sustained release profile for potential application in localized osteoporosis therapy. This study advances the design of photopolymerizable resins for SLA-based scaffold fabrication. It highlights how the integration of components with different physical and chemical properties can lead to homogeneous hybrid biomaterials that address the limitations of individual components. These findings lay a strong foundation for enhancing resin-based 3DP technologies in BTE and regenerative medicine.