Preparation of Calcium Phosphate Fibers by Electrospinning Technique

Electrospinning is a simple and versatile technique to produce submicron fibers. Electrospun inorganic fibers have potential applications as tissue engineering scaffolds and as components of dental composite materials. Understanding the factors that control fiber architecture will allow the custom fabrication of appropriate structures for specific biomedical applications.

Objective: To investigate the effects of applied voltage and flow rate on the architecture of electrospun calcium phosphate fibers

Methods: Calcium nitrate and triethyl phosphite sol-gel precursors were combined with an aqueous solution of polyvinylpyrrolidone and electrospun from a glass syringe equipped with an 18 gauge needle. The flow rate and voltage ranged between 0.05-0.2 mL/h and 17-25 kV, respectively. The collecting distance was 8.4 cm. The resulting material was heated and subsequently calcined at 600֩C to obtain residual inorganic fibers. Fibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA).

Results: TGA of the electropun fibers demonstrated two weight loss stages, with no further weight loss over 500֩C, indicating removal of residues. A carbonate-substituted apatitic structure of the calcined fibers was suggested by FTIR. Electron microscopy revealed various fiber architectures, including hollow tubular fibers (17 kV, 0.05 mL/h), solid fibers (25 kV, 0.05 mL/h), and porous fibers (17 kV, 0.2 mL/h; 25 kV, 0.2 mL/h). The diameter of the calcined fibers ranged between 100-170 nm and 0.5-1.2 µm.

Conclusions: We have established a simple and versatile approach for the fabrication of calcium phosphate fibers with controllable architecture (including nanotubes, solid and porous fibers). This will allow the fabrication of fibers appropriate for specific medical and dental applications.

This work was supported by the Natural Sciences and Engineering Research Council of Canada.