Novel synthesis of BCP cotton-wool-like nanofibrous scaffolds by air-heated solution blow spinning (A-HSBS) technique

Abstract

Biphasic calcium phosphate (BCP) cotton-wool-like nanofibrous scaffolds are very interesting materials for tissue engineering. Air-heated solution blow spinning (A-HSBS) was a simple and novel strategy developed in this work to obtain this structure. Precursor solutions of calcium nitrate, triethyl phosphate, and polyvinylpyrrolidone (spinning agent) dissolved in water and ethanol were used. The scaffolds were calcined at 800 °C. Part of the samples was stored under restricted atmospheric conditions, while the other part was exposed to ambient conditions for 7 days. The scaffolds were characterized by thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. In vitro assays were performed using simulated body fluid (SBF) and phosphate-buffered saline (PBS) solutions. Results showed the formation of scaffolds constituted by intertwined nanometric fibers. XRD patterns indicated the formation of BCP and CaO. For the sample exposed to air, CaCO3 was formed from the conversion of CaO with atmospheric CO2, producing BCP/CaCO3. After 7 days of immersion in SBF solution, the formation of a homogeneous layer of apatite was more evident on the surface of the BCP/CaCO3 than on the BCP nanofibers. The biodegradability in PBS medium, after 14 days of immersion, showed a mass loss of 21% (pH of 8.3) and 14% for the BCP and BCP/CaCO3 scaffolds (pH of 7.8), respectively. BCP nanofibrous scaffolds can be considered promising candidates for use in bone tissue engineering applications.