Addition of Bone-Marrow Mesenchymal Stem Cells to 3D-Printed Alginate/Gelatin Hydrogel Containing Freeze-Dried Bone Nanoparticles Accelerates Regeneration of Critical Size Bone Defects.

A 3D-printed biodegradable hydrogel, consisting of alginate, gelatin, and freeze-dried bone allograft nanoparticles (npFDBA), was developed as a scaffold for enhancing cell adhesion, proliferation, and osteogenic differentiation when combined with rat bone marrow mesenchymal stem cells (rBMSCs). This composite hydrogel was intended for the regeneration of critical-sized bone defects using a rat calvaria defect model. The behavior of rBMSCs seeded onto the scaffold was evaluated through SEM, MTT assays, and quantitative real-time PCR. In a randomized study, thirty rats were assigned to five treatment groups: 1) rBMSCs-loaded hydrogel, 2) rBMSCs-loaded FDBA microparticles, 3) hydrogel alone, 4) FDBA alone, and 5) an empty defect serving as a negative control. After 8 weeks, bone regeneration was assessed using H&E, Masson's trichrome staining, and immunohistochemistry (IHC). The 3D-printed hydrogel displayed excellent adhesion, proliferation, and differentiation of rBMSCs. The rBMSCs-loaded hydrogel exhibited comparable new bone regeneration to the rBMSCs-loaded FDBA group, outperforming other groups with statistical significance (P value < 0.05). These findings were corroborated by Masson's trichrome staining and osteocalcin expression. The rBMSCs-loaded 3D-printed hydrogel demonstrated promising potential for significantly enhancing bone regeneration, surpassing the conventional clinical approach (FDBA). This article is protected by copyright. All rights reserved.