Emulsion electrospun PLA/calcium alginate nanofibers for periodontal tissue engineering.

Objective The regeneration of periodontal bone tissue is a major obstacle in tissue engineering. We have recently designed a compound nanofiber scaffold for the tissue repair of periodontal bone, which was composed of poly(lactic acid) (PLA) and calcium alginate (CA). The obtained improvements in both physical properties and biological effects on periodontal tissue were systematically evaluated and discussed. Method Neat PLA and PLA/CA nanofiber scaffolds were prepared by electrospinning technology. Scanning electron microscopy was applied for the observation of surface morphology. Their mechanical properties were evaluated in terms of elongation at break and elastic modulus. Hydrophilic/hydrophobic nature of the nanofibers was investigated by a stereomicroscope, and their vitro degradation was tested as well. Cell proliferation and adhesion were detected in order to evaluate the biocompatibility of nanofiber scaffolds. Expression of cell mineralization gene and formation of mineralization knots were examined so as to assess scaffolds' capability of regenerating bone tissues. The expression of Toll-like receptor 4 (TLR4), IL-6, IL-8, and IL-1 beta was utilized to decide the possibility of tissue inflammation caused by the nanofibers with the assistance of reverse transcription-polymerase chain reaction (RT-PCR) assay. Results The obtained nanofibers possessed uniform surface morphology. The elongation at break and elastic modulus of PLA/CA nanofiber scaffolds were higher than those of neat PLA. CA could enhance the hydrophilicity of PLA fibers; in the meantime, it promoted cell adhesion of periodontal ligament cells (PDLCs) and bone marrow stromal cells (BMSCs). Addition of CA had raised the expression level of cell mineralization gene and the formation of mineralization knots (BMSCs). On the other hand, both neat PLA fibers and PLA/CA fibers could induce higher expression level of inflammatory mediators and TLR4 of human periodontal ligament cells (hPDLCs). Conclusions The introduction of CA enhanced the mechanical properties of neat PLA nanofibers and increased its hydrophilicity. Neat PLA nanofibers and PLA/CA scaffold could both facilitate BMSCs proliferation, while the addition of CA promoted BMSCs osteogenic differentiation. The improved (or enhanced) expression of inflammatory mediators caused by nanofibers might be regulated via TLR4 pathway.