Controlled Synthesis of Hydroxyapatite Using a Novel Natural Rosin-Based Surfactant

Hydroxyapatite (HAP) with multiform morphologies, such as hollow dandelion-like bundles and nanoparticles with a diameter of 50 nm, was prepared using natural rosin-based surfactant dehydroabietyl phosphate diester (DDPD) as phosphorus source, crystal growth control agent, and template simultaneously by a facile hydrothermal method. Samples were obtained and characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results showed that DDPD and pH value of solution were the key factors for the morphology of HAP. Hollow dandelion-like bundles HAP, containing the Ca-monodehydroabietyl phosphate (PM-Ca) organic metal compounds, were formed at pH = 3 without acid-base regulation, and nanoparticles were obtained at pH = 12. SEM exhibited that the hollow dandelion-like bundles HAP are of 10 mu m (outer) and 1 mu m (inner) diameter, respectively. Cell viabilities are above 95% when the cells are co-cultured with all HAP samples at concentrations in the range of 250-1000 mu g/ml. It indicated that the prepared HAP with PM-Ca has a good cytocompatibility without apparent toxicity. Finally, the possible formation mechanism of the HAP microstructures was discussed in detail.