Silica/polycaprolactone nanofiber scaffold variants for human periosteal cell growth

Polycaprolactone (PCL) nanofiber scaffolds with attached cadaveric human periosteum or its cells were investigated in this study as a tissue-engineering approach to repair nonunion injuries of bone. Addition of silica nanoparticles (silica or nSiO₂ ) to PCL scaffolds was examined for effects on the growth of human periosteal cells in vitro and in vivo. Electrospun PCL nanofiber (nanoPCL) scaffolds were fabricated with different silica contents (0, 0.5, and 1.0 wt %) and utilized as substrates on which periosteal cells were seeded. Human periosteal cell growth analyzed in vitro over 21 days with a PrestoBlue viability assay increased as a function of culture time on each of the three different silica/nanoPCL scaffolds. Cadaveric periosteum attached to nanoPCL scaffolds with or without silica was wrapped around allograft bone and implanted for 10 or 20 weeks in athymic (nude) mice. Histological and immunohistochemical analyses of these experiments in vivo confirmed the presence of viable cells populating the constructs after their retrieval from host mice. Osterix, a marker for osteoblasts, increased in retrieved constructs over time and indicated remodeling of the underlying allograft bone. Summary results suggest that silica/nanoPCL scaffolds may be utilized as substrates for periosteal cell and tissue expansion to augment and support clinical applications for treatment and healing of bone defects, including segmental bone injuries and nonunions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 791-801, 2019.