Bioactivity and osteoblast responses of novel biomedical nanocomposites of bioactive glass nanofiber filled poly(lactic acid)

Abstract

Biomedical nanocomposites constituted of bioactive ceramic and resorbable polymer have shown promise for the successful regeneration of bone tissues. We developed herein a novel nanocomposite made up of a bioactive glass in a nanofibrous form and a degradable synthetic polymer, poly(lactic acid) (PLA). The glass nanofiber with a bioactive composition was generated via an electrospinning process with an average diameter of approximately 320 nm. The nanofiber was homogenized with PLA solution at various concentrations (up to 35% nanofiber), followed by drying and thermal pressing to produce dense nanocomposites. The nanocomposites showed an internal morphology of uniformly dispersed nanofibers within the PLA matrix. The nanocomposites induced rapid formation of a hydroxycarbonate apatite layer on the surface under a simulated physiological medium. As the amount of bioactive nanofiber increased (from 5 to 25%), the in vitro bioactivity of the nanocomposite was improved. The osteoblast responses to the nanocomposites (compositions with 5 and 25% nanofiber) were assessed in terms of cell proliferation, differentiation, and mineralization. Osteoblasts attached and grew well on the nanocomposites and secreted collagen protein at initial culturing periods. The differentiation of cells, as assessed by the expression of alkaline phosphatase, was significantly improved on the nanocomposites as compared to those on pure PLA. Moreover, the mineralized product by the cells was observed to be significantly higher on the nanocomposites with respect to pure PLA. The newly developed nanocomposite constituted of bioactive nanofiber and degradable polymer is considered as a promising bone regeneration matrix with its excellent bioactivity and osteoblast responses.