Fabrication And Osteogenic Evaluation Of Biomimetic Electrospinning Scaffolds Loaded With Lysophosphatidic Acid Nanoparticles

Research purposes:Treatment of bone defects is limited because it’s difficult selfhealing.With the development of tissue engineering,bone regeneration materials have emerged.Electrospinning scaffolds have high porosity,large surface area and 3D structure similar to extracellular matrix.These properties can enhance the interaction between cells and the surface of the scaffolds,and then promote cell adhesion,proliferation and migration.Moreover,using biodegradable scaffolds can avoid secondary operations,prevent infection,and relieve the suffering of patients.Electrospinning scaffolds can be loaded with a variety of bioactive substances such as growth factors,antibiotics and so on.Its substrate coating can guarantee the stable release of active substances.In this study,the electrospinning scaffolds loaded with Lysophosphatidic Acid(LPA)nanoparticles were fabricated and its physicochemical properties and bone regeneration ability were explored.Research methods:The self-made LPA nanoparticles and nano-hydroxyapatite(nHA)particles were added into the PLGA/PCL material matrix,and the functional scaffolds PPnHA-LPA ES were obtained by electrospinning technology.PP ES,PP-LPA ES and PP-nHA ES were prepared in the same way as the control.Field emission scanning electron microscope(FE-SEM),Fourier transform infrared attenuated total reflection infrared spectroscopy(ATR-FTIR)spectrophotometer,universal testing machine were respectively.used to investigate the surface morphology,surface functional groups and mechanical properties of the scaffolds.MC3T3-E1 cells CCK-8 assay was used to test cell viability and proliferation.Alkaline phosphatase kit was used to detect the activity of alkaline phosphatase(ALP).The expression levels of cell adhesion molecule,integrin β1 were qualitatively detected by Immunofluorescence.Expression level of bone formation-related genes RUNX2 and BMP-2 were detected by Real-time quantitative polymerase chain reaction(RT-PCR).Biocompatibility was tested by subcutaneous implantation.The mouse maxillary bone defect model was established to evaluate the osteogenic effect of the scaffolds after implantation in vivo.Results:The PP-nHA-LPA ES had a 3D bionic scaffold structure with improved mechanical properties due to the successful introduction of active substances.The CCK-8 results showed that PP-nHA-LPA ES significantly promoted MC3T3-E1 cells proliferation(P<0.001)and had no toxic side effects.ALP results showed that PP-nHA-LPA ES effectively promoted the differentiation of osteoblasts compared to PP ES(P<0.01),indicative of the synergistic effect of bioactive molecules released from the modified scaffolds.The qualitative Immunofluorescence analysis results demonstrated that the expression of integrin β1 in PP-nHA-LPA ES was significantly increased.RT-PCR assay showed that the expression level of bone formation-related gene RUNX2,BMP-2 in PPnHA-LPA ES were significantly higher than that in PP ES(P<0.001).Subcutaneous implantation experiments showed that all four scaffolds had good biocompatibility and the biocompatibility of PP-nHA-LPA ES were the best.PP-nHA-LPA ES effectively promoted osteogenesis after being implanted in the mouse maxillary bone defect model for 4 weeks.The designed PP-nHA-LPA ES achieved its osteogenic properties approaching to the commercial collagen membranes "Bio-Gide" and "Haiao".Conclusions:The electrospinning scaffolds loaded with LPA and nHA have stable 3D structure,strengthened mechanical properties,good biocompatibility and excellent capability for enhancing bone regeneration.It might potentially be a new ideal material for repairing bone defects.