Rapid production of bioactive hydroxyapatite fibers via electroblowing

Submicron hydroxyapatite fibers were fabricated by electroblowing followed by annealing. Solutions of Ca(NO3)2∙4H2O, triethyl phosphate and polyvinylpyrrolidone dissolved in ethanol and water were used for the electroblowing. The annealed membranes consisted of randomly oriented fibers characterized as hydroxyapatite by X-ray diffraction. Solution blow spinning of hydroxyapatite was also attempted, but the resulting fiber membranes incorporated large beads and were overall of poor quality compared to the electroblown fibers. With electroblowing the hydroxyapatite fibers were prepared at a fast rate of 1.38 g/h, a significant improvement over the production rate obtainable in conventional needle electrospinning. In simulated body fluid (SBF) a continuous apatite layer was found to form around the hydroxyapatite fibers in just six hours suggesting high bioactivity. SBF immersion up to 7 days led to an increase in densification of the apatite layer and further increase in its thickness. The fibers can thus be considered promising for bone scaffold applications.