The treatment of bone tissue defects continues to be
a complex
medical issue. Recently, three-dimensional (3D)-printed scaffold technology
for bone tissue engineering (BTE) has emerged as an important therapeutic
approach for bone defect repair. Despite the potential of BTE scaffolds
to contribute to long-term bone reconstruction, there are certain
challenges associated with it including the impediment of bone growth
within the scaffolds and vascular infiltration. These difficulties
can be resolved by using scaffold structural modification strategies
that can effectively guide bone regeneration. This study involved
the preparation of biphasic calcium phosphate spherical hollow structural
scaffolds (SHSS) with varying pore sizes using 3D printing (photopolymerized
via digital light processing). The chemical compositions, microscopic
morphologies, mechanical properties, biocompatibilities, osteogenic
properties, and impact on repairing critical-sized bone defects of
SHSS were assessed through characterization analyses, in vitro cytological
assays, and in vivo biological experiments. The results revealed the
biomimetic properties of SHSS and their favorable biocompatibility.
The scaffolds stimulated cell adhesion, proliferation, differentiation,
and migration and facilitated the expression of osteogenic genes and
proteins, including Col-1, OCN, and OPN. Furthermore, they could effectively
repair a critical-sized bone defect in a rabbit femoral condyle by
establishing an osteogenic platform and guiding bone regeneration
in the defect region. This innovative strategy presents a novel therapeutic
approach for assessing critical-sized bone defects.