Study On The Mesenchymal Stem Cell Differentiation Into Osteoblast Induced By Bio–Mimetic Micro&Nano Structures

Because of its good mechanical and biological properties pure titanium has been extensively used in the field of implants.and the surface treatment technologies of pure titanium has made good bone combined effect in recent years,but the time of early integration needs to be further shortened.On account of their multipotent differentiation potentials,bone marrow mesenchymal stem cells(MSC)have been widely used in biomedical engineering field,such as bone tissue engineering.By the method of building a micro-nano structure in implant surface which is useful for the osteoblast differentiation of MSC to shorten the bone integration period,has become one of the hotspots in the implant surface processing field.In this work,we analyzed the effect of different laser processing parameters on micro-nano structure of titanium surface,prepared four special micro-nano bionic structures on the surface of pure titanium by femtosecond laser,at last improve their biological activity by alkali treatment.The results of hydrophilic,microhardness,corrosion resistance and hydroxyapatite induction ability show that the bone implant performance of pit and stripe structures treated by alkali after laser processing are better than the samples of polished and treated by sand blasting in combination with acid-etching.We also studied the biological behavior of cells on the surface of micro-nano structures.It proved to be that the micro-nano structure of samples treated by alkali after laser processing and sand blasting in combination with acid-etching are conducive to the adhesion and proliferation of MC3T3-E1 and MSC,in terms of promoting effect,the pit and stripe structures processed by femtosecond laser are better than the sample treated by sand blasting in combination with acid-etching.In addition,through the morphological analysis we know that cells grew with obviously orientation when they were administered in the surface of micro-nano structures.The differentiation of MSC on surface of different samples show that,in the case of with and without differentiation inducer,the micro-nano structures treated by alkali after laser processing all promote the differentiation of MSC into osteoblasts.In two kinds of induction conditions,the cells inoculated on the surface of pit and stripe structures are in the best growth state and with higher degree of osteogenesis differentiation than the surface treated by sand blasting in combination with acid-etching.In conclusion,the pit and stripe structures treated by alkali after femtosecond laser processing improve the biological performance of titanium.It provides a favorable micro environment for the proliferation of MC3T3-E1 and the directional osteoblastic differentiation of MSC.The results of this study can provide a reference for the preparation of new micro-nano structure of implants.