Aligned hydroxyapatite nano-crystal formation on a polyamide surface

Controlling the orientation of well-crystallized nano-hydroxyapatite (n-HA) remains a difficult task because of the complicated process of n-HA crystallization. In the present research, highly aligned n-HA arrays were fabricated on a polyamide matrix. The oriented n-HA crystals were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). The mechanism of how these structures form was explored. The results show that the oriented n-HA arrays are formed on a calcium treated polyamide matrix. The diameter of the n-HA columns is about 47.41 +/- 3.02 nm. The n-HA crystals grow vertically with the substrate and the length of the crystals is 613.423 +/- 61.57 nm. Osteoblast-like MG63 cells were cultured on the nano-crystals in order to demonstrate the biocompatibility of these oriented n-HA crystals. The MTT assay suggests that the oriented n-HA crystals could promote cell proliferation. The overall results indicate the promising potential of oriented n-HA crystals for bone regeneration.