Enhanced bone formation using hydroxyapatite ceramic coated with fibroblast growth factor-2

Current bone grafting techniques face limitations in controlled growth factor release. While hydroxyapatite ceramics are widely used for bone substitutes, their ability to deliver bioactive molecules remains underexplored. Prior research has shown that fibroblast growth factor-2 (FGF-2) can stimulate bone regeneration when applied exogenously. However, maintaining FGF-2 bioactivity during delivery remains a challenge. No prior work had resolved how to coat ceramics with FGF-2 while preserving its function. This gap motivated the development of a system where FGF-2 is immobilized on a scaffold for sustained release. The uncertainty around optimal FGF-2 concentrations for bone formation also remains unresolved. That uncertainty drove the investigation into whether hydroxyapatite ceramics could serve as a controlled release platform for FGF-2. This study introduces a novel approach to bone substitute design.

This study aimed to determine whether hydroxyapatite ceramic could be used to deliver FGF-2 in a controlled manner. The specific problem addressed was the need for a bone substitute that can release bioactive FGF-2 at effective concentrations. The motivation stemmed from the limitations of current bone grafting materials, which often lack sustained growth factor delivery. The researchers proposed that coating hydroxyapatite with FGF-2 could enhance bone regeneration. The study sought to evaluate both the release profile and bioactivity of FGF-2 from the coated ceramic. A second objective was to compare low and high FGF-2 doses in terms of bone formation efficacy. The team also aimed to detect in vivo FGF-2 release by measuring BMP-2 expression. This approach could lead to improved bone substitute materials with enhanced regenerative potential.

Hydroxyapatite ceramic buttons were coated with FGF-2 using a precipitation method in a supersaturated calcium phosphate solution. Two groups were created: one with high FGF-2 dose (FGF-H) and another with low dose (FGF-L). The release of FGF-2 from these coated ceramics was evaluated in vitro using a release profile and bioactivity tests. A rat model with parietal bone defects was used to assess bone formation. Four treatment groups were tested: HAP-CBs alone, HAP-CBs with FGF-2 solution, FGF-L, and FGF-H. Bone morphogenic protein-2 (BMP-2) expression was measured in defective bone tissue to detect in vivo FGF-2 release. The study design included both in vitro and in vivo experiments to validate the system’s functionality. The use of a controlled release platform allowed for the evaluation of FGF-2 bioactivity over time. This method enabled the researchers to assess both the release kinetics and biological effects of the coated ceramic.

FGF-2 was successfully released from both FGF-H and FGF-L in vitro, and the released protein retained bioactivity. Rats treated with FGF-L showed significantly better bone formation than those in other groups. BMP-2 expression was detected in defective bone tissues of FGF-L-treated rats at 14 days, suggesting in vivo FGF-2 release. The high-dose FGF-H group did not outperform the low-dose group in terms of bone regeneration. This finding indicates that a specific FGF-2 concentration may be optimal for bone formation. The release profile of FGF-2 from the ceramic was consistent with bioactivity preservation. The study demonstrated that hydroxyapatite ceramics can serve as a controlled release platform for FGF-2. The results suggest that the system can deliver FGF-2 at concentrations sufficient to induce bone formation.

The study demonstrated that hydroxyapatite ceramics can be coated with FGF-2 in a way that preserves its bioactivity. The coated ceramics released FGF-2 in vitro and showed evidence of in vivo release through BMP-2 expression. Rats treated with the low-dose FGF-2 ceramic showed better bone formation than other groups. The authors propose that a specific FGF-2 concentration is necessary for optimal bone regeneration. The system allows for controlled FGF-2 delivery at effective concentrations. The results suggest that this approach could improve bone substitute performance. The study supports the potential of hydroxyapatite ceramics as a platform for growth factor delivery. The findings may guide future development of bone graft materials with enhanced regenerative properties.