Stereocomplex poly(lactic acid)-based composite nanofiber membranes with highly dispersed hydroxyapatite for potential bone tissue engineering

Abstract The development of materials with excellent mechanical properties and stem cell affinity for bone repair is a topic that has received significant interest in the field of bone tissue engineering. In this study, stereocomplex poly(lactic acid)-based composite nanofiber membranes that are compatible with bone marrow stem cells (BMSCs) were prepared with poly( d -lactic acid)-grafted hydroxyapatite and enantiomeric poly(lactic acid)s. The mechanical property tests showed that, compared with those from a heated poly( l -lactic acid) (PLLA) nanofiber membrane, the tensile strength and Young's modulus of the most strengthened composite nanofiber membrane herein increased by 30.16% and 34.56%, respectively. The X-ray diffraction results indicated that the stereocomplex crystallite (SC) of poly(lactic acid) formed in heated composite nanofiber membranes. The differential scanning calorimetry results showed that the melting temperature of the SC of heated composite nanofiber membranes was approximately 221 °C. Live/dead staining and scanning electron microscopy were used to observe the proliferation and adhesion of BMSCs cultured on the nanofiber membranes. Compared with the PLLA nanofiber membrane, increased type I collagen expression and improved formation of bone-like nodules can be observed after induction for nine days on the composite nanofiber membrane, indicating the potential application of the composite nanofiber membrane for bone tissue engineering.