RESUMO
Nanofibrous materials produced by electrospinning processes have potential advantages in tissue engineering because of their biocompatibility, biodegradability, biomimetic architecture, and excellent mechanical properties. The aim of the current work is to study the influence of the electron beam on the poly L-lactide acid/ carboxy-methyl starch/ß-tricalcium phosphate (PLLA/CMS/ß-TCP) composite nanofibers for potential applications as bone-tissue scaffolds. The composite nanofibers were prepared by electrospinning in the combination of 5% v/v carboxy-methyl starch (CMS) and 0.25 wt% of ß-TCP with the PLLA as a matrix component. The composites nanofibers were exposed under 5, 30, and 100 kGy of irradiation dose. The electron-beam irradiation showed no morphological damage to the fibers, and slight reduction in the water-contact angle and mechanical strength at the higher-irradiation doses. The chain scission was found to be a dominant effect; the higher doses of electron-beam irradiation thus increased the in vitro degradation rate of the composite nanofibers. The chemical interaction due to irradiation was indicated by the Fourier transform infrared (FTIR) spectrum and thermal behavior was investigated by a differential scanning calorimeter (DSC). The results showed that the electron-beam-induced poly L-lactide acid/carboxy-methyl starch/ß-tricalcium phosphate (PLLA/CMS/ß-TCP) composite nanofibers may have great potential for bone-tissue engineering.
RESUMO
A natural polymer of carboxymethyl starch (CMS) was used in combination with the inorganic mineral of ß-Tricalcium Phosphate (ß-TCP) and Poly l-lactide (PLLA) to prepare composite nanofibers with the potential to be used as a biomedical membrane. ß-TCP contents varied in the range of 0.25% to 1% in the composition of PLLA and CMS. A mixed composition of these organic and inorganic materials was electro-spun to produce composite nanofibers. Morphological investigation indicated that smooth and uniform nanofibers could be produced via this technique. The average of the nanofiber diameters was slightly increased from 190 to 265 nm with the ß-TCP content but some agglomeration of particles began to impede in the fiber at a higher content of ß-TCP. It was observed that the fibers were damaged at a higher content of ß-TCP nanoparticles. With the presence of higher ß-TCP, the wettability of the PLLA was also improved, as indicated by the water contact angle measurement from 127.3° to 118°. The crystallization in the composite decreased, as shown in the changes in glass transition (Tg) and melting temperature (Tm) by differential scanning calorimeter (DSC) and X-ray diffraction analysis. Increases in ß-TCP contributed to weaker mechanical strength, from 8.5 to 5.7 MPa, due to imperfect fiber structure.