Preparation of electrospun poly(lactic acid)-based hybrids containing siloxane-doped vaterite particles for bone regeneration.

Siloxane/poly(L-lactic acid)/vaterite hybrid (SiPVH) fibremats constantly release calcium ions and ionic silicon species that have the potential to promote bone regeneration. In order to improve the mechanical properties of the SiPVH fibremats, the effect of various silixane-containing vaterite (denoted by SiV) content (10-60 wt%) on tensile properties was assessed. SiPVH fibremats with 30 wt% SiV content showed the highest tensile strength of 2.87 ± 0.39 MPa. Based on the energy-dissipation mechanism, failure initiated at the stress concentration points such as pores on the fibre surfaces or filler particles. In the case of the SiPVH fibremats with 20 and 30 wt% SiV, stress concentration occurred around the filler particles, where the applied energy was directly converted to small volume dilatation around the filler particles during failure of the fibres. This mechanism can be applied only when the material contains the polymer and the filler particles in specific ratios; 20 and 30 wt% filler content in the fibremat in this work. To coat the fibre surfaces with bone-like apatite SiPVH fibremats were soaked in modified simulated body fluid (1.5 SBF). Bone-like apatite formed on the surfaces of SiPVH fibremats with more than 30 wt% of SiV content in 1 day of soaking. These results reveal that the SiPVH fibremats containing 30 wt% SiV have suitable mechanical properties for bone filler materials.