Modified poly(L-lactic acid) microspheres with nanofibrous structure suitable for biomedical application

Aminolyzed poly(L-lactic acid) (EPLA) microspheres with nanofibrous structure were prepared for the first time by aminolysis combined with emulsion and thermally induced phase separation technique from a ternary ethylenediamine aqueous solution/poly(L-lactic acid) (PLLA)-dioxane/propanetriol system. The results indicated that ethylenediamine concentration, aminolyzing time, and ratio of dioxane to ethylenediamine in aqueous solution significantly influenced the morphology and structures of microspheres. Under optimum conditions, monodispersed microspheres with nanofibrous structure were obtained. The in vitro bioactivity test showed that EPLA nanofibrous microspheres exhibited a strong apatite-formation ability compared with unmodified PLLA microspheres without nanofibrous structure, indicating that the bioactivity of PLLA microspheres was significantly improved through aminolysis reaction with ethylenediamine. [GRAPHICS]