In Vitro Biological Evaluation Of Ti6Al4V By Micro-Arc Oxidation

Objective and background:Titanium and titanium alloy used in the medical science has a long history,which has good mechanical properties and biocompatibility.Titanium and its alloy can be implanted in the body environment instead of joints,teeth and other hard tissue structures.Although titanium and its alloys are widely used in clinical practice,there are some shortcomings.Titanium has low biological activity,poor osteogenic ability,long time of bone-implants integration cycle in the clinical.The micro-arc oxidation is a hot spot in the surface modification of materials in recent years.It directly generates porous bioceramic films on the surface of titanium alloy.The titanium alloy and the surface layer are metallurgically bonded,and the film contains a large amount of hydroxyapatite.The biofilm was formed on the surface of Ti6Al4 V was evaluated in vitro biocompatibility.ALP is an important marker of early differentiation,which the beginning of osteogenic differentiation.SP7 is an important factor in the early osteogenesis differentiation process,which has the effect of inducing the differentiation of stem cells into osteoblasts and regulating the transcription of related genes.SP7 can regulate COLL-I,OPN and other related osteogenic factors.Osteogenic factors COLL-I,OPN,OCN are all closely related factors in osteogenic mineralization.The main structural protein of bone tissue of COLL-I plays a role in the induction of bone formation.OPN is an important marker of osteoblast differentiation.OCN is a key factor in bone formation.It is the only specific determinant of osteoblast formation.Its gene regulation needs to be carried out on the basis of collagen synthesis.ALP,SP7,COLL-I,OPN and OCN were the important factors in osteoblast differentiation process,osteogenic transcription factor and osteogenic factor to express osteoblast differentiation.In this study,biofilm was generated on the surface of Ti6Al4 V by one-step micro-arc oxidation.The biocompatibility was evaluated by in vitro cell experiments.The expression of ALP,SP7,COLL-I,OPN,OCN and other factors were observed.Evaluation.Methods:1.In this study,using MAO technology,we produce the films with hydroxyapatite on the surface of titanium alloy.2.Surface properties: The surface morphology and surface composition of the materials were characterized by SEM.3.In the CCK-8 test,vat liquor with different concentrations from the modified surface mterial from MAO were used to culture MG-63 cells.It is the way to test the cytotoxicity.4.Micro-arc oxidation biofilm formation of titanium alloy for the experimental group,the control group was untreated Ti6Al4 V and SLA with Ti6Al4 V.The cells were culured respectivievly on the different surfaces,to evaluate the cell proliferation,the ALP activity and the relative expression of related osteogenic genes.Rerults:1.Scanning electron microscopy: the surface of the material was crater structure with the diameter of 20-50 um.There are many ceramic sintered particles on the surface of the film,which are mainly on the inner wall of the pore size of the film.The surface of the film has hydroxyl apatite,calcium phosphate and rutile phase,in which the hydroxyapatite is the main peak phase,which indicates that the main component of the oxide film is hydroxyapatite.2.The surface cytotoxicity of the micro-arc oxidation was 0,it was non-toxic for cells.3.The results showed that the cell proliferation rate in the micro-arc oxidation group was higher than that in the other two groups.The activity of ALP in the micro-arc oxidation group was significantly higher than that in the other two groups,and then decreased.And the results were still higher than those of the other two groups.The real time PCR results showed that the expression of osteogenic genes in the surface cells after micro-arc oxidation was higher than that in the other two groups.The relative expression of COLL-|,SP7 reached the maximum.OCN,OPN expressed the maximum value on the 5th day.In summary,one-step micro-arc oxidation can produce porous biofilm on the surface of titanium alloy.The surface is mainly hydroxyapatite and others.The surface was untoxic for cells and promote osteoblast proliferation and differentiation.