Micro-nano Structures Prepared By Layer-by-Layer Self-assembly Technique Effect On Osteogenesis Of Adipose-derived Stem Cells

Objective:To expand the application of electrospun films in bone tissue engineering,they were surface modified by nanoparticles using Lay-by-Layer(LbL)self-assembly technique to fabricate micro-nano structures,with the purpose to enhance the hydrophilicity and biocompatibility,so as to promote the osteogenic differentiation of the stem cells seeded on them.Method:?-Fe2O3,?-Fe2O3 and gold nanoparticles were assembled onto the electrospinning fibers by LbL method,and marked as ?-Fe2O3 group,?-Fe2O3 group and Au group.The blank films were used as the control.The four groups were then assessed for morphology and magnetic properties by Scanning electron microscope(SEM),Transmission electron microscope(TEM),Attenuated total reflection flourier transformed infrared spectroscopy(ATR-FTIR)and Vibrating sample magnetometer(VSM).Rat adipose-derived stem cells(rADSCs)were seeded onto the films.The adhesion and proliferation of the stem cells was detected by Confocal laser scanning microscope(CLSM)and Cell counting kit-8(CCK-8).While osteogenic differentiation was detected by Quantitative real-time PCR(qRT-PCR).Results:SEM showed that the electrospun film had a three-dimensional structure with numerous pores.After LbL coated with nanoparticles,the films retained its fiber diameter and structural characteristics.TEM indicated that the electrospun fibers were evenly wrapped with nanoparticles.VSM presented that the films modified by?-Fe2O3 had superparamagnetism,however the magnetic strength was much less than that of ?-Fe2O3 solution.Compared to the blank group,cells were observed to adhere better to and extend fully on the three coated groups by CLSM.Quantitative results showed that Au group was more favorable to cells' adhesion.The CCK-8 results demonstrated that there was no obvious cytotoxicity in all the three coated groups compared with blank control,but Au group had a role in promoting cell proliferation.According qRT-PCR results,the expression of osteoblast-related genes on ?-Fe2O3 group was highest of all the groups.Conclusion:?-Fe2O3,?-Fe2O3 and gold nanoparticles were successfully grafted onto the electrospun films by LbL self-assembly method.Compared with the control group there was no cytotoxicity of all the composite films.Gold nanoparticles coated electrospun film could promote the adhesion,proliferation and osteogenic differentiation of stem cells,while superparamagnetic iron oxide coated electrospun film could significantly promote the osteogenic differentiation of stem cells.