Effects of β-Tricalcium Phosphate on the Growth of Rat Osteoblasts

1Introduction Hydroxyapatite,akindofcalcium phosphatecrystal isthemostabundantpartinnaturalbonesandteeth.βtricalciumphosphate(βTCP)biomaterialisartificial preparedformedicalapplicationofbone defect fillingand stomatologicoperationsbecauseofitsbetterbiocompati bilityandosteoconductivityamongthecalcium phosphate materials.ItwasobservedthatTCPcouldbedegradedin vivo,andintheculturedosteoclastsinvitro[1,2].During itsdegradation,dicalciumphosphatedihydrateandocta calciumphosphatewereformed.Atla…     

Bone Formation Process of β-TCP Ceramics with Tetracycline Tracing

To stndy the new bone formation in the bone defect area after implantation, the tetracycline tracing method was used. The results show that new bone formed in 1 month, and the formation rate of new bone was very high (8.164um/day), cunsiderably faster than that of control groups ( 3.219um / day ). The new bone grew up quickly and β-TCP particles were surrounded by double fluorescence bands which became more obvious. The new bone formation rate was maximal at 2 months, and then grndually reduced. The rate was steady at 4 months, and then reduced to resembling as the normal physiologic metabolism of bone, which indicated the implanted materials were completely replaced by bone. Calcium phosphate materials had the ability of osteoconduction .     

Effects of β-TCP Ceramics on Intracellular Ca~(2+) Concentration,Mineralization of Osteoblast and Protein Structure

β-TCP, as one of calcium phosphates ceramics, exerts perfect biocompatibility and osteoconductivity, and is clinically used as a bone graft substitute for decades. Consequently, the effects of β-TCP ceramics on intracellular Ca2+ concentration, mineralization of osteoblast and BSA protein structure were studied. Results showed that β-TCP could increase the intracelluar Ca2+ concentration and mineralization of osteoblast, indicating that β-TCP ceramics could take part in the organic metabolism and the degrad...     

Preparation and Characterization of β-TCP/CS Scaffolds by Freeze-extraction and Freeze-gelation

The freeze-extraction and freeze-gelation methods were used to prepare highly porous β-TCP/CS scaffolds with different β-TCP/CS ratio.In these methods,the suspending mixture of β-TCP and chitosan was frozen,the frozen mixture was immersed in a non-solvent(0.05mol/L NaOH/ehanol aqueous) bath to allow the exchange between solvent(acetic-acid aqueous) and non-solvent at a temperature lower than the freezing point of the acetic-acid.Then,the β-TCP/CS scaffolds were formed and dried at room temperature.Scanning ...     

The Influence of Type and Thickness of Sol-gel Derived Coatings on the in vitro Osteoblasts Behavior

To evaluate the cellular response to the most commonly studied coatings fabricated by the sol-gel route, the influence of the coating thickness on the cellular response was studied. 1, 3, 5 layers of hydroxyapatite （ HA ）, fluorohydroxyapatite （ FHA ） and titania （ TiO2 ） were coated on the surface of commercially pure titanium （ cpTi ） discs respectively by the sol- gel route. CpTi discs were taken as control. XRD and SEM were employed to characterize the type and thickness of these coatings. In vitro osteoblasts behavior on the coatings was studied by the culture of MG63 cell line. The experimental results show all groups have good biocompatibilhy to osteoblasts . However, the type and thickness of the coatings influence the osteoblast response. The optimal type and thickness of sol-gel derived biocoatings were concluded.     

Effect of Grinding and Polishing on the Residual Stress and Bending Strength of a Silicon Nitride Ceramic

The residual stresses on the surface of the differently ground and polished silicon nitride ceramics were measured using X- ray diffraction and identified by SEM. The effect of the residual stress on the bending strength was investigcaed. The investigatious show that the grinding process can introduce subatantial teusile residual stresses up to 290 MPa on the surface of silicon nitride ceramics, which has a significant effect on reducing the bending strength of the ceramics after grinding. Thus, in comparison with the ceramics with a rongh surface, the ceramics with a mirror image surface may bave a lower strength. Polishing can smooth the residual stresses. When we evaluate the quality of the ceramic components after grinding, we must take residual stress into consideration. The grinding methods and grinding conditions must be carefully selected in order to get the favorite residual stress as well as the surface smoothness.     

Effect of a bone graft substitute β tricalcium phosphate on osteoblastic genes mRNA exprssion

To investigate the molecular aspects of osteoblastic interactions with β tricalcium phosphate (β-TCP) particles, human osteoblast-like MG-63 cells were cultured with β-TCP particles at a density of 6 mg/mL culture medium for 48 h. Then, the mRNA expression of selected genes were quantified by real-time polymerase chain reaction (PCR), including the attachment-related genes (α integrin and actin), the proliferation-related gene (c-jun), and the osteoblastic markers genes (type I collagen, osteonectin, alkaline phosphatase, RUNX2 and osteoclain). The results showed that β-TCP particles (the average size 809 nm) significantly promote the attachment and the proliferation of MG-63 cells, and slightly enhance the osteoblastic differentiation based on the analyses of the related genes expression. This study provided scientific evidences to better reveal the underlines of functions of β-TCP in bone repair.     

Effect of Lead Contents on the Properties of PMSZT Piezoelectric Ceramics

The effects of Pb content on crystallographic phase, microstructure, electric-properties of PMSZT piezoelectric ceramics were studied. The crystallographic phase and microstructure of the ceramics were examined by using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The experimental result shows that the samples consist of a mixture of tetragonal and rhombohedral phases in the range of lead contents x=0.95-1.06, grains grow up homogeneously and the minimum value of Curie temperature was obtained with x-=1.02. With Pb content x〈l.02 or x〉1.02, the Curie temperature moves towards a high temperature. A well-situated electric-properties of ET33/E0 （1660）, d33 （344pC/N）, Kp （0.684）, Qm （2350）,tan 3（0.0030） were obtained when lead content x=1.02.     

In-situ growth and photoluminescence of β-Ga_2O_3 cone-like nanowires on the surface of Ga substrates

β-Ga2O3 cone-like nanowires have been in-situ grown on the surface of gallium grains and films by heating gallium substrates at 750—1000℃ for 2h in air.The controllable synthesis of β-Ga2O3 nano-wires with different diameters and lengths was achieved by adjusting the heating temperature and time.The as-synthesized products were characterized by means of X-ray diffraction,scanning electron mi-croscopy and transmission electron microscopy.The results showed that the β-Ga2O3 nanowires are single crystalline wi...     

Effect of Li content on the microstructure and properties of lead-free piezoelectric （K0.5Na0.5）1-xLixNbO3 ceramics prepared by SPS

Lead-free piezoelectric （K0.5sNa0.5）1-xLixNbO3 （x = 0at%-20at%） ceramics were synthesized by spark plasma sintering （SPS） at low temperature and the effects of LiNbO3 addition on its crystal structure and properties were also studied. When the Li content was less than 6at%, a single proveskite phase with the similar structure of （K0.5Na0.5）NbO3 was formed; and a secondary phase with K3Li2Nb5O15 structure was observed in the 6at% 〈 x 〈 20at% compositional range. Furthermore, LiNbO3 existed as the third phase when the Li content was higher than 8at%. The grain sizes increased from 200-500 nm to 5-8 μm when the K3Li2Nb5O15 and LiNbO3 like phases were formed. With increasing Li content, the relative density of the ceramics first decreased from 97% to 93% and then kept constant. The piezoelectric coefficient d33, dielectric constant, and planner electromechanical coupling factor exhibited a decreasing tendency with increasing Li content because of the decrease in density and the formation of the secondary phase such as K3Li2Nb5O15 and LiNbO3. The formation of dense microstructure with a single phase is necessary in improving the properties of the （K0.5Na0.5）1-xLixNbO3 ceramics.