Hybrid bioactive hydroxyapatite/polycaprolactone nanoparticles for enhanced osteogenesis

Hydroxyapatite nanoparticles (HApN) are largely employed as osteogenic inorganic material. Inorganic/polymeric hybrid nanostructures can provide versatile bioactivity for superior osteogenicity, particularly as nano particles. Herein, we present hybrid biomaterial-based hydroxyapatite/polycaprolactone nanoparticles (HAp/ PCL NPs) realized using simple preparation techniques to augment HApN osteogenicity. Using wet chemical precipitation, we optimized HApN crystalline properties utilizing a 2(3)-factorial design. Optimized HApN exhibited typical Ca/P elemental ratio with high reaction yield. Surface area analysis revealed their mesoporous nature and high surface area. Hybrid HAp/PCL NPs prepared using direct emulsification-solvent evaporation maintained HApN crystallinity with no observed chemical interactions. To the best of our knowledge, we are the first to elaborate the biocompatibility and osteogenicity of nanoparticulate hybrid HAp/PCL. Hybrid HAp/PCL NPs outperformed HApN regarding mesenchymal cell proliferation and osteodifferentiation with reduction of possible cytotoxicity. Unlike HApN, hybrid HAp/PCL NPs presented moderate expression of early osteogenic markers, Runx-2 and osteopontin and significantly elevated expression of the late osteogenic marker, bone sialoprotein after 10-day culture. Our results indicate that hybrid bioactive HAp/PCL NPs could offer a more prominent osteogenic potential than plain HApN for bone regenerative applications as a standalone nanoplatform or as part of complex engineered systems.

Automated summary

Hybrid biomaterial-based hydroxyapatite/polycaprolactone nanoparticles (HAp/PCL NPs) were prepared to enhance osteogenicity, showing superior performance in mesenchymal cell proliferation and osteodifferentiation with reduced cytotoxicity. The hybrid NPs also exhibited moderate expression of early osteogenic markers and significantly elevated expression of late osteogenic markers, suggesting a promising potential for bone regenerative applications.