Text

Objectives and questions: Bone injuries and congenital deformities present significant challenges in orthopedic healthcare, often requiring advanced surgical interventions. Traditional bone grafts face limitations in cases of substantial bone loss due to complications like limited availability and rejection risks. Tissue-engineered bone implants offer a potential solution, designed to support, regenerate, and augment defective bone tissue. This study aims to develop synthetic bone implants that enhance bone longevity, minimize patient discomfort, and reduce the need for revision surgeries. By overcoming the limitations of conventional grafts, particularly for large bone defects, this work explores the transformative potential of tissue-engineered implants in orthopedic care.

Materials and methods: Nano-structured fluorapatite-fluorcanasite biominerals were synthesized as bioactive reinforcements using a top-down approach. These biominerals were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM), and in-vitro cell culture assays. Porous composite bone implants were fabricated by incorporating these biominerals into a poly-(ε-caprolactone) (PCL) biopolymer matrix. A hybrid fabrication technique combining thermally induced phase separation (TIPS)/solvent casting with fused deposition modeling (FDM) was used to create implants with meso-, micro-, and macro-scale porosity. These implants were characterized for microstructural and mechanical properties, biodegradability in phosphate-buffered saline (PBS), and biocompatibility with osteosarcoma human bone cells (MG63).

Results: Fluorcanasite-fluorapatite nano-particulates displayed needle-like structures, with crystalline phases resembling the nano-ceramic architecture of natural bone. The porous composite implants exhibited excellent biocompatibility, bioactivity, and biodegradability, supporting bone regeneration and reducing the risk of revision surgeries. Their lightweight nature reduced patient discomfort. The implants' highly interconnected porous network, featuring meso- and micro-pores with macro channels, facilitated cellular infiltration and accelerated bone formation. This structure ensured efficient nutrient and mineral transport to defect sites while maintaining mechanical strength for large bone defects.

Discussion and conclusions: The fluorapatite-fluorcanasite biomineralized composite bone implants hold promise in addressing critical bone defects. The integration of these bioactive materials within a PCL matrix promotes cellular survival and bone regeneration. The implants' interconnected porosity and mechanical properties make them a promising solution for bone regeneration, potentially eliminating revision surgeries. However, further optimization and in-vivo evaluations are needed to assess clinical efficacy. These implants represent a significant advancement in bone tissue engineering, with strong potential for use in regenerative medicine and treating complex bone injuries.