Statement of problem. To improve a direct implant fixation to the bone, various strategies have been developed focusing on the surface of materials. The surface quality of the implant depends on the chemical, physical, mechanical and topographical properties of the surface. The different properties ...
Statement of problem. To improve a direct implant fixation to the bone, various strategies have been developed focusing on the surface of materials. The surface quality of the implant depends on the chemical, physical, mechanical and topographical properties of the surface. The different properties will interact with each other and a change in thickness of the oxide layer may also result in a change in surface energy, the surface topography and surface, chemical composition. However, there is limited the comprehensive study with regard to changed surface and biologic behavior of osteoblast by anodization. Purpose of study. The aim of this study was to analyze the characteristics of an oxide layer formed and to evaluate the cellular biologic behaviors on titanium by anodic oxidation (anodization) by cellular proliferation, differentiation, ECM formation and gene expression. And the phospholipase activity was measured on the anodized surface as preliminary study to understand how surface properties of Ti implant are transduced into downstream cellular events. Methods and Materials. The surface of a commercially pure titanium(Grade 2) was modified by anodic oxidation. The group 1 samples had a machined surface and other three experimental specimens were anodized under a constant voltage of 270 V(Group 2), 350 V(Group 3), and 450 V(Group 4). The specimen characteristics were inspected using the following five categories; the surface morphology, the surface roughness, the thickness of oxide layer, the crystallinity, and the chemical composition of the oxide layer. Cell numbers were taken as a marker for cell proliferation. While the expression of alkaline phosphatase and Runx2 (Cbfa1) was used as early differentiation marker for osteoblast. The type I collagen production was determined, which constitutes the main structural protein of the extracellular matrix. Phospholipase $A_2$ and D activity were detected. Results. (1) The anodized titanium had a porous oxide layer, and there was increase in both the size and number of pores with increasing anodizing voltage. (2) With increasing voltage, the surface roughness and thickness of the oxide film increased significantly (p<0.01), the $TiO_2$phase changed from anatase to rutile. During the anodic oxidization, Ca and P ions were more incorporated into the oxide layer. (3) The in vitro cell responses of the specimen were also dependant on the oxidation conditions. With increasing voltage, the ALP activity, type I collagen production, and Cbfa 1 gene expression increased significantly (p<0.01), while the cell proliferation decreased. (4) In preliminary study on the relation of surface property and phospholipase, PLD activity was increased but $PLA_2$ activity did not changed according to applied voltage. Conclusion. The anodized titanium shows improved surface characteristics than the machined titanium. The surface properties acquired by anodization appear to give rise more mature osteoblast characteristics and might result in increased bone growth, and contribute to the achievement of a tight fixation. The precise mechanism of surface property signaling is not known, may be related to phospholipase D.
Statement of problem. To improve a direct implant fixation to the bone, various strategies have been developed focusing on the surface of materials. The surface quality of the implant depends on the chemical, physical, mechanical and topographical properties of the surface. The different properties will interact with each other and a change in thickness of the oxide layer may also result in a change in surface energy, the surface topography and surface, chemical composition. However, there is limited the comprehensive study with regard to changed surface and biologic behavior of osteoblast by anodization. Purpose of study. The aim of this study was to analyze the characteristics of an oxide layer formed and to evaluate the cellular biologic behaviors on titanium by anodic oxidation (anodization) by cellular proliferation, differentiation, ECM formation and gene expression. And the phospholipase activity was measured on the anodized surface as preliminary study to understand how surface properties of Ti implant are transduced into downstream cellular events. Methods and Materials. The surface of a commercially pure titanium(Grade 2) was modified by anodic oxidation. The group 1 samples had a machined surface and other three experimental specimens were anodized under a constant voltage of 270 V(Group 2), 350 V(Group 3), and 450 V(Group 4). The specimen characteristics were inspected using the following five categories; the surface morphology, the surface roughness, the thickness of oxide layer, the crystallinity, and the chemical composition of the oxide layer. Cell numbers were taken as a marker for cell proliferation. While the expression of alkaline phosphatase and Runx2 (Cbfa1) was used as early differentiation marker for osteoblast. The type I collagen production was determined, which constitutes the main structural protein of the extracellular matrix. Phospholipase $A_2$ and D activity were detected. Results. (1) The anodized titanium had a porous oxide layer, and there was increase in both the size and number of pores with increasing anodizing voltage. (2) With increasing voltage, the surface roughness and thickness of the oxide film increased significantly (p<0.01), the $TiO_2$phase changed from anatase to rutile. During the anodic oxidization, Ca and P ions were more incorporated into the oxide layer. (3) The in vitro cell responses of the specimen were also dependant on the oxidation conditions. With increasing voltage, the ALP activity, type I collagen production, and Cbfa 1 gene expression increased significantly (p<0.01), while the cell proliferation decreased. (4) In preliminary study on the relation of surface property and phospholipase, PLD activity was increased but $PLA_2$ activity did not changed according to applied voltage. Conclusion. The anodized titanium shows improved surface characteristics than the machined titanium. The surface properties acquired by anodization appear to give rise more mature osteoblast characteristics and might result in increased bone growth, and contribute to the achievement of a tight fixation. The precise mechanism of surface property signaling is not known, may be related to phospholipase D.
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문제 정의
reported upon the relationship between phospholipid metabolism and osteoblast differentiation in MG63 cells.23 The main objective of present preliminary study was to. evaluate the potential and differential activation of phospholipasesz such as PLA2 or PLDZ by modified surface property of Ti in MG63 cells based on the our experimental results of lipid composition analysis (Data are not shown).
가설 설정
1. The anodized titanium had a porous oxide layer, and there was increase in both the size and number of pores with increasing anodizing voltage.
3. The in vitro cell responses of the specimen were also dependant on the oxidation conditions. With increasing voltage, the ALP activity, type I collagen production, and Cbfa 1 gene expression increased, while the cell proliferation decreased.
Roughness and oxide layer were increased M, A350V and A450V in turn. From this result, we hypothesize the rougher implant surface, the sooner the Cbfal gene expresses. The early expression of Cbfal in MG63 cells on Ti disc of increased surface roughness or topographic complexity is congruent with in vivo observations regarding the extent of osteogenesis on implants of increasing surface roughness.
제안 방법
The crystal structure and microstructure of the specimens were evaluated by X-ray diffraction (XRD; M18XHF-SRA, Mac Science Cov Yokohama, Japan) analysis and scanning electron microscopy (SEM; JSM-5600, JEOL, Tokyo, Japan), respec-tiv이y. The composition of the surface layer was analyzed with EDS(INCA, Oxford, England).
To identify the effect of anodization, the biological properties of the layers were evaluated by in vitro tests, in terms of the proliferation, differentiation, ECM formation, and gene expression. The preliminary study was also carried out to confirm the involvement of phospholipases during signaling of surface property modified by anodic oxidation treatment of Ti surface in MG63 cells.
The results are plotted specific PLD activity as a the percentage of [3H]PBt in total lipid and represent the means ± SD of four independent experiments with 6 replicates. Statistical significance were tested by ANOVA.
2 The response of cell and tissue to implant is affected by not only the chemical properties but also the surface topography or roughness of the implant surface. Therefore, we investigated TIO2 layers with different thickness and roughness on the Ti surface, by controlling the applied voltage used in this study, The crystal structure, composition and morphology of the oxide layer were monitored with respect to the applied voltage for anodization. To identify the effect of anodization, the biological properties of the layers were evaluated by in vitro tests, in terms of the proliferation, differentiation, ECM formation, and gene expression.
The area of measurement was 80/Ltm x 80ym. Three parameters, the average roughness (Ra), 10 point average roughness (Rz) and Peak-to-Valley height (Rmax) were used to characterize the roughness of the specimens. The oxide thickness was estimated by disc sectioning and the sectioned surface was examined with SEM.
Therefore, we investigated TIO2 layers with different thickness and roughness on the Ti surface, by controlling the applied voltage used in this study, The crystal structure, composition and morphology of the oxide layer were monitored with respect to the applied voltage for anodization. To identify the effect of anodization, the biological properties of the layers were evaluated by in vitro tests, in terms of the proliferation, differentiation, ECM formation, and gene expression. The preliminary study was also carried out to confirm the involvement of phospholipases during signaling of surface property modified by anodic oxidation treatment of Ti surface in MG63 cells.
To investigate the potential influences of anodized treatments on the osteogenic key marker Runx2 gene expression, MG63 cells were incubated on different discs for 1 days, 3 days, and lday after visual confluence. The expression of Runx2 gene was examined using Reverse transcription PCR and the electrophoresis result is shown in Fig.
23 The main objective of present preliminary study was to. evaluate the potential and differential activation of phospholipasesz such as PLA2 or PLDZ by modified surface property of Ti in MG63 cells based on the our experimental results of lipid composition analysis (Data are not shown). These enzymes are considered to play an important role as effector enzymes in membrane lipid mediated signal transduction.
대상 데이터
The specific activity was calculated referring to protein concentration of lysates. Experiments were performed in 6 replicates, and the activity was averaged from four independent experiments.
For experiments rat cal.,arial osteoblast-like cells and human osteosarcoma MG63 cells were used. Cells were isolated from cal.
,aria of 1-2 day old rats and collected and cultured in aminimal essential medium (a- MEM : Gibco, USA) containing 10% fetal bovine serum (FBS) and 1% antibiotics-antimycotics (Gibco, USA). MG63 cells were obtained from the American Type Culture Collection (Rockvill, MD, USA). C이Is were sedded of 2 x 105 cells in RPMI1640 medium (Gibsco BRL, Grand Island, NY, USA) 10% heat inactivated FBS and lOU/ml penicilline / streptomycin.
The results are plotted as a percentage of the PLD activity in control cells and represent the means±SD of four independent experiments with 6 replicates. Statistical significance were tested by ANOVA (P>0.
데이터처리
Statistical significance were tested by ANOVA (P<0.01).
replicates. Statistical significance were tested by ANOVA (P>0.05).
Statistical significance were tested by ANOVA. The asterica indicate significant difference between groups (P<0.
이론/모형
Statistical significance were tested by Kruskall-Wallis test.
Among the techniques, which have been found to be beneficial to the biological performance of the implants, are increasing the surface roughness and the oxidation of Ti to form a TiO? layer on the surface. The method used in this study for preparing porous oxide surface was anodic oxidation, an electrochemical method. In anodic oxidation (anodization), the ionic current and the processes at the electrode lead to the growth of an eventually oxide film (anodic oxide).
성능/효과
2. With increasing voltage, the surface roughness and thickness of the oxide film increased significantly (p<0.01)z the TiOi phase changed from anatase to rutile. During the anodic oxidization, Ca and P ions were more incorporated into the oxide layer.
4. In preliminary study on the relation of surface property and phospholipase, PLD activity was increased, but PLA2 activity did not changed according to applied voltage.
후속연구
We should consider the effect and interaction of not only roughness but also chemical composition and the characteristics of surface microstructure on Cbfal expression. Therefore, further studies that focus on the different effects of chemical composition, microstructure and oxide layer with same roughness on cell behaviors will be required.
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