Bi-layered calcium phosphate cement-based composite scaffold mimicking natural bone structure

Natural bone has a hierarchical structure that includes dense cortical and porous cancellous regions. Current scaffolds struggle to replicate this dual architecture while maintaining mechanical and biological properties. Prior research has shown that single-layered scaffolds often fail to match the mechanical strength of natural bone. That uncertainty drove the development of multi-layered constructs. No prior work had resolved how to balance compressive strength with pore interconnectivity in bi-layered scaffolds. Researchers propose that mimicking natural bone structure could improve bone repair outcomes. This gap motivated the design of a bi-layered composite scaffold. The challenge lies in achieving both structural and functional similarity to native bone.

The aim of this study was to fabricate a bi-layered composite scaffold that mimics the natural structure of cortical and cancellous bone. The goal was to create a scaffold with adjustable mechanical properties and suitable for bone repair. The researchers propose that a dual-layer design could better support cell proliferation and tissue regeneration. The specific problem addressed is the lack of scaffolds that balance compressive strength with pore connectivity. The motivation stems from the need for improved bone repair materials. The study sought to test whether a bi-layered structure could enhance scaffold performance. The authors suggest that such a scaffold could better support bone marrow stromal cell growth. The design aimed to replicate the mechanical and structural features of natural bone.

The scaffold was fabricated using a core/shell approach with calcium phosphate cement (CPC). The dense shell was created through isostatic pressing of CPC powder in a custom mold. A porous core was produced via unidirectional freeze casting inside the shell cavity. The freeze casting method generated a lamellar pore structure. Poly(lactic-co-glycolic acid) was infiltrated into the porous core. Collagen was immobilized on the scaffold to enhance biological activity. The compressive strength was adjusted by varying the thickness ratio of the dense and porous layers. The scaffold’s mechanical and structural properties were evaluated using standard testing methods.

The bi-layered scaffold achieved adjustable compressive strength based on layer thickness ratios. The dense shell provided structural integrity while the porous core maintained pore interconnectivity. In vitro tests showed that rat bone marrow stromal cells attached and proliferated on the scaffold. The pore structure supported cell infiltration and nutrient transport. The scaffold’s unidirectional interconnectivity was preserved despite limited three-dimensional connectivity. The mechanical properties matched those of natural bone in certain configurations. The addition of collagen enhanced cell adhesion and proliferation. The results suggest that the scaffold supports bone repair applications.

The authors propose that the bi-layered CPC-based composite scaffold mimics natural bone structure effectively. The scaffold’s adjustable compressive strength and pore interconnectivity support bone repair. The in vitro results suggest that the scaffold is suitable for cell proliferation and attachment. The design balances mechanical and biological properties. The authors suggest that the scaffold could be used in clinical bone repair applications. The study supports the idea that mimicking natural bone architecture improves scaffold performance. The findings suggest that the scaffold has potential for future use in bone regeneration. The authors propose that further in vivo testing is necessary to confirm clinical viability.