In vitro evaluation of an yttria-stabilized zirconia reinforced nano-hydroxyapatite/polyamide 66 ternary biomaterial: biomechanics, biocompatibility and bioactivity

Abstract

Nano-hydroxyapatite/polyamide 66 (nHA/PA66) is a bioactive composite that is widely applied in orthopedics. However, imperfect mechanical behavior is the main drawback of the nHA/PA66 composite, and this is a limitation for further applications. Meanwhile, zirconia has been attracting increasing attention in recent years, owing to its excellent mechanical behavior and biocompatibility. A novel ternary biomaterial composed of nHA/PA66/yttria-stabilized tetragonal zirconia (YTZ) was prepared in the present research. The material was analyzed by X-ray diffraction and Fourier transform infrared spectrometry; mechanical behavior was also tested. The results of the mechanical-behavior testing showed that the mechanical behaviors of nHA/PA66/YTZ were significantly better than those of nHA/PA66. Besides, the cross-section of this biocomposite was characterized by scanning electron microscopy. Furthermore, the biocompatibility and bioactivity were evaluated in vitro using MC3T3-E1 cells. From the results of the biocompatibility and bioactivity experiments (cell counting kit-8 tests, cell immunofluorescence analysis, alizarin red S staining and western blotting), it was observed that nHA/PA66/YTZ could facilitate the biological function of MC3T3-E1 cells. The results showed that the attachment, proliferation, spreading, calcium nodule formation, and expression of osteogenic-related proteins (collagen 1, osteopontin, osteocalcin) of cells cultured with the nHA/PA66/YTZ composite were better than for control groups. The ternary biomaterial has promising mechanical properties, biocompatibility and bioactivity. Thus, it deserves more attention and is worthy of further research.