Nanohydroxyapatite (HA) is a well-established synthetic bone substitute with excellent osteoconduction and osteointegration. However, brittleness coupled with slow degradation curtail its load bearing and bone regeneration potential respectively. To address these limitations, nanoHA composite matrix reinforced with electrospun 1D fibrous yarns was fabricated and tested in vitro and in vivo. Different weight percentages (5, 10, 15 wt%) and varying lengths (short and continuous) of PLLA yarns were randomly dispersed in a gelatinous matrix containing nanoHA. This significantly improved the compressive strength as well as work of fracture, especially for continuous yarns at high weight percentages (10 and 15 wt%). Incorporation of yarns did not adversely affect the pore size (50 - 350 µm) or porosity of the scaffolds as well as its in vitro cellular response. Finally, when tested in a critical sized femoral segmental defect in rat, the nanocomposite scaffolds induced osteoblast cell infiltration at two months that subsequently underwent increased mature lamellar bone formation at four months, in both the mid and peripheral defect regions. Histomorphometric analysis demonstrated that both new bone formation and biomaterial degradation were significantly enhanced in the composite scaffold when compared to HA. Overall, the composite matrix reinforced with electrospun yarns proved to be a potential bone substitute having an appropriate balance between mechanical strength, porosity, biodegradation and bone regeneration ability.
A. A. Nair, Joseph, J., Dr. Deepthy Menon, Shantikumar V Nair, and Dr. Manitha B. Nair, “Electrospun Yarn Reinforced NanoHA Composite Matrix as a Potential Bone Substitute for Enhanced Regeneration of Segmental Defects.”, Tissue Eng Part A, 2017.