Bone augmentation using a highly porous PLGA/β-TCP scaffold containing fibroblast growth factor-2

Beta-tricalcium phosphate (β-TCP) is known to support bone conductivity. It has been used in bone tissue engineering due to its bio-absorbable properties. However, β-TCP scaffolds often lack sufficient mechanical strength for clinical use. This limitation has motivated researchers to explore ways to enhance scaffold performance. Previous studies have shown that coating β-TCP with polymers like PLGA can improve mechanical properties. Yet, the impact of such modifications on bone augmentation remains unclear. This uncertainty drove the current investigation into combining β-TCP with PLGA and growth factors. The study aimed to assess whether these modifications could improve bone formation outcomes. No prior work had resolved the specific effects of FGF-2 loading on PLGA/β-TCP scaffolds.

The primary aim was to evaluate the effectiveness of a PLGA/β-TCP scaffold loaded with fibroblast growth factor-2 (FGF-2) in promoting bone augmentation. The specific problem addressed was the mechanical weakness of β-TCP scaffolds, which limits their clinical utility. The motivation stemmed from the need to develop a scaffold that maintains high porosity while offering improved strength. The study also sought to determine if FGF-2 could enhance bone formation when delivered via such a scaffold. Researchers aimed to test the scaffold's biocompatibility and structural properties. They focused on whether the PLGA coating could preserve porosity while increasing mechanical stability. The study also examined how FGF-2 influences new bone growth in vivo. The ultimate goal was to assess the scaffold's potential for bone tissue engineering applications.

The β-TCP scaffold was fabricated using the replica method with polyurethane foam as a template. A thin layer of poly lactic acid/glycolic acid (PLGA) was applied to the scaffold to enhance mechanical strength. The scaffold was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to assess surface morphology. X-ray diffraction was used to evaluate crystallinity, while compressive testing measured mechanical properties. Cell culture experiments assessed biocompatibility, and subcutaneous implant tests were conducted in animals. A bone-forming test was performed in 52 rats, with scaffolds implanted into cranial bone. Histological analysis occurred at 10 and 35 days post-implantation. The study compared scaffolds with and without FGF-2 loading to evaluate its effect on bone augmentation.

SEM and TEM confirmed a thin PLGA layer on β-TCP particles after coating. The scaffold maintained high porosity (>90%) following PLGA application. Compressive strength increased six-fold compared to noncoated scaffolds. The PLGA/β-TCP scaffold showed good biocompatibility in both cell culture and implantation tests. Histological samples from rats implanted with FGF-2-loaded scaffolds revealed significant bone augmentation. The control scaffolds without FGF-2 showed less pronounced bone formation. The combination of PLGA coating and FGF-2 loading enhanced scaffold performance. These findings suggest that the modified scaffold supports effective bone regeneration.

The study demonstrated that PLGA coating improves the mechanical strength of β-TCP scaffolds without reducing porosity. Histological evidence supports the effectiveness of FGF-2-loaded scaffolds in promoting bone augmentation. The authors propose that combining PLGA with β-TCP and FGF-2 is a promising strategy for bone tissue engineering. No prior work had established this specific combination's efficacy. The results suggest that the scaffold's biocompatibility and structural properties are suitable for clinical applications. The findings align with the hypothesis that FGF-2 delivery via PLGA/β-TCP scaffolds enhances bone regeneration. The study's implications are limited to the observed effects in the rat model. Further research could explore the scaffold's long-term performance in larger animals.