Doping and Incorporation of Hydroxyapatite in Development of PU-PLA Electrospun Osteogenic Membranes

Abstract

Complete restoration of bones to treat oral and craniofacial skeletal disorders, presents a challenge for orthopedic and maxillofacial experts. In the present research hydroxyapatite (HA) the main constituent of bone, has been modified with various dopants to enhance the biological as well as mechanical properties of skeletal tissue. The doped bioactive HA powder has been incorporated in the polymeric matrix of polyurethane (PU) and poly l lactic acid (PLLA) to fabricate osteogenic membranes. Four different composites were fabricated with dopants such as Sr, Mg, SiO4, and CO3 and were named as PU-PLA-Sr-HA, PU-PLA-Mg-HA, PU-PLA-Si-HA and PU-PLA-C-HA. The prepared osteogenic membranes were characterized using FTIR, XRD and EDX analyses. In vitro characterization was done to evaluate cell proliferation and calcium deposition using the MC3T3 pre-osteoblast cell line on the membranes. The mechanical properties i.e. tensile strength was also evaluated with respect to dopant types and their concentration. FTIR, XRD and EDX spectral analyses confirm the various dopings in the prepared HA powder. PU-PLA-Sr-HA membranes exhibit porous fibers with uniformly distributed pores along the surface of fibers. The tensile strength of membranes containing doped HA was higher than the membrane without adding HA powder. The Young’s modulus of PU-PLA-Mg-HA and PU-PLA-Si-HA membranes was higher compared to the other samples. Lowest Young’s modulus value was observed in the PU-PLA-Sr-HA membrane. Cell viability assay displayed very high biocompatibility for all the prepared membranes, specifically PU-PLA-C-HA and PU-PLA-Sr-HA membranes showed higher cell proliferation. Moreover, the doped HA incorporated membranes showed increased deposition of calcium through the Alizarin Red assay. In conclusion the electrospun fibrous membranes with doped HA displayed improved osteogenic properties and hence can be an excellent candidate for bone and dental regenerative applications.