Electrospun polycaprolactone incorporated with fluorapatite nanoparticles composite scaffolds enhance healing of experimental calvarial defect on rats

BACKGROUND: Composite scaffolds that maximize the advantages of different polymers are widely utilized in guided tissue regeneration (GTR). Some studies found that novel composite scaffolds composed of electrospun polycaprolactone/fluorapatite (ePCL/FA) actively promoted the osteogenic mineralization of various cell types in vitro. However, only a few studies have addressed the application of this composite scaffold membrane material in vivo. In this study, the ability of ePCL/FA composite scaffolds in vivo and their possible mechanisms were preliminarily explored. METHODS: In this study, ePCL/FA composite scaffolds were characterized and their effects on bone tissue engineering and repair of calvarial defects in rats were examined. Sixteen male Sprague-Dawley (SD) rats were randomly categorized into four groups: normal group (integral cranial structure without defect), control group (cranial defect), ePCL group (cranial defect repaired by electrospun polycaprolactone scaffolds), and ePCL/FA group (cranial defect repaired by fluorapatite-modified electrospun polycaprolactone scaffolds). At 1 week, 2 months, and 4 months, micro-computed tomography (micro-CT) analysis was performed to compare the bone mineral density (BMD), bone volume (BV), tissue volume (TV), and bone volume percentage (BV/TV). The effects of bone tissue engineering and repair were observed by histological examination (hematoxylin and eosin, Van Gieson, and Masson respectively) at 4 months. RESULTS: In water contact angle measurement, the average contact angle for the ePCL/FA group was significantly lower than that for the ePCL group, indicating that the FA crystal improved the hydrophilicity of the copolymer. Micro-CT analysis revealed that the cranial defect had no significant change at 1 week; however, the BMD, BV, and BV/TV of the ePCL/FA group were significantly higher than those of the control group at 2 and 4 months. Histological examination showed that the cranial defects were almost completely repaired by the ePCL/FA composite scaffolds at 4 months compared to the control and ePCL groups. CONCLUSIONS: The introduction of a biocompatible FA crystal improved the physical and biological properties of the ePCL/FA composite scaffolds; thus, these scaffolds demonstrate outstanding osteogenic potential for bone and orthopedic regenerative applications.