Scaffolds híbridos nanofibrilares de PLA/PEG/fosfato de cálcio produzidos por solution blow spinning.

Abstract

Calcium phosphates have been extensively investigated for application in the biomedical field due to their bioactivity and biocompatibility. However, the brittle nature of these materials limits their application as scaffolds for tissue engineering. This feature can be overcome by the use of hybrid materials. Thus, the objective of this study was to produce nanofibrillary scaffolds of poly (lactic acid) / poly (ethylene glycol) / calcium phosphate (PLA / PEG / CaP) by means of the solution blow spinning technique (SBS). Calcium nitrate tetrahydrate and triethyl phosphate (TEP) were used as inorganic precursors and a polyvinylpyrrolidone (PVP) polymer solution was used as the guiding agent for the production of CaP nanofibers. The CaP nanofibers were produced by SBS, Ca / P ratio equal to 1.67 and 1.1, and calcined at 1000 ° C. To produce the scaffolds, the CaP nanofibers were macerated and dispersed in dimethyl carbonate solvent (DMC) and then PEG and PLA were added to the solutions to be further subjected to the spinning process also by SBS. Final concentrations of PEG in the scaffolds ranged from 20 to 30%. The nanofibers and scaffolds produced were characterized by X-ray diffraction (XRD), thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission (TEM) and bioactivity assay. From the obtained results it was possible to note that for both Ca / P ratios there was formation of HAp as the

main phase. However, for Ca / P = 1.1, a small amount of calcium triphosphate (β- TCP) was formed. The diffraction patterns and the thermogravimetric results

confirmed the formation of the organic / inorganic hybrid. The morphological analysis of scaffolds showed that the addition of PEG made it possible to reduce defects in their morphology. After bioactivity assays in PBS it was possible to observe a better deposition of the apatite layer on the surface of CaP composite scaffolds with ratio = 1.1, over the 14 day test period. In conclusion, it was possible to obtain hybrid scaffolds with randomly interconnected and highly porous structure with good dispersion of the CaP load, in addition, scaffolds with higher CaP percentage indicate better bioactivity to induce calcium mineralization for bone regeneration.