Study On Osteogenic Properties Of Titanium-Ta Biogradient Materials

Objectives In this experiment,pure titanium surfaces with different morphologies and compositions were prepared by surface treatment of titanium sheets with different methods.In vitro experiments were conducted to evaluate the effects of different treated pure titanium surfaces on the biological behavior of bone marrow mesenchymal stem cells(BMSCs),and to explore the surface treatment methods conducive to the mineralization of pure titanium surface.Methods The experimental groups were divided into untreated smooth titanium sheet group,acid etched hydrothermal group and acid etched hydrothermal plus plasma sprayed tantalum group(hereinafter referred to as tantalum coating group),each group consisted of 9 pieces.1 Isolation,culture and identification of bone marrow mesenchymal stem cells in SD rats: primary bone marrow tissue cells were cultured by tissue block method,and surface markers of BMSCs in the third generation were detected by immunofluorescence method;osteogenesis and adipogenesis were induced in the third generation of BMSCs.2 Cell morphology and adhesion: BMSCs of the third generation rats were inoculated onto three groups of different titanium surfaces.After 24 hours of culture,the cells were stained by fluorescence,and the morphological differences of each group were observed under inverted fluorescence microscope.BMSCs of the third generation of rats were inoculated onto three different groups of titanium sheets.After 4,8 and 12 hours of culture,the cells on the titanium sheets were digested and made into cell suspension.The cells were counted by cell counting plate.3 Alkaline phosphatase assay: BMSCs of the third generation rats were inoculated on three groups of different titanium plates.After 3/5/7 days of culture,ALP levels of cells on three groups of samples were measured by ALP kit.4 Observation of mineralized nodules and determination of calcium ion concentration: After 11 days of culture,BMSCs were stained with alizarin red staining solution on three groups of specimens,and mineralized nodules were observed under stereomicroscope,and the level of calcium deposition was detected by enzyme labeling instrument.Results 1 Identification of bone marrow mesenchymal stem cells in SD rats: CD34-,CD44+,can be seen under fluorescence microscope,which accords with the characteristics of BMSCs surface markers;under inverted microscope,mineralizednodules can be observed after osteogenesis induction,and lipid droplets can be seen after adipogenesis induction,indicating that cells have the ability of osteogenesis and adipogenesis differentiation.2 Cell adhesion morphology and quantity: the smooth pure titanium group had insufficient cell spreading and small cell volume;the acid-etched hydrothermal group had sufficient cell spreading and pseudopodia extending;the tantalum-coated group had sufficient cell spreading and polygonal cells with more pseudopodia.After 4,8 and 12 hours of cell culture,the number of cell adhesion on the surface of specimens was tantalum spraying group > acid etching hydrothermal group > smooth pure titanium group(P < 0.05).3 ALP activity of cells on the surface of specimens: on the third day of cell culture,the acid etching hydrothermal group and tantalum spraying group were higher than smooth pure titanium group(P < 0.05);on the fifth and seventh day,the tantalum spraying group was higher than acid etching hydrothermal group(P < 0.05).4 Observation of mineralized nodules and determination of calcium ion concentration on the surface: Under stereomicroscope,the staining area of Ta spraying group and acid etching hydrothermal group was larger and deeper,while that of smooth titanium group was thinner.Among the quantitative results of calcium ions,tantalum spraying group > acid etching hydrothermal group > smooth titanium sheet group(P < 0.05).Conclusions: 1 Rat bone marrow stem cells cultured by tissue block method conform to the characteristics of mesenchymal stem cells.2 The titanium surface treated by acid etching and hydrothermal treatment can promote the adhesion,differentiation and mineralization of bone marrow stem cells.3 Ta plasma spraying on the surface of pure titanium treated by acid etching and hydrothermal treatment can improve the osteogenesis of surface cells.Figure8;Table5;Reference 95...