| Bone defect and bone fracture are common orthopaedic disease, their treatment oftendepends on the application of bone tissue replacement materials. Developing newelectroactive bone substitute materials to promote bone tissue repair and regeneration andshorten the recovery period has potential clinical application prospect. Basing on the electricalactivity of the biological organism, organization, and biological molecules and the biologicalactivity demand of hard tissue replacement materials, in this paper, the potassium sodiumniobate piezoelectric ceramic preparation and its performance research were carried out.During the particles preparation process, the ball milling time of8h, calcinationtemperature of700°C is considered to be the optimal technology parameter of potassiumsodium niobate powders preparation route, basing on the experiment results of the sizedistribution, thermogravimetry-differential thermal analysis, microscopic morphology andphase analysis of the as-received particles and the relative density, piezoelectric constant ofthe ceramic that fabricated with corresponding particles.During the fabrication of ceramics, the relative density, piezoelectric constant andwettability of potassium sodium niobate ceramics, prepared via different sintering temperature,were tested. With the increase of sintering temperature, ceramic density increases, and itspiezoelectric constant also will increase, but when the sintering temperature close to themelting temperature, volatile elements lead to phase segregation, the piezoelectric phasecomposition decreases, and the corresponding piezoelectric constant decreases. At lowsintering temperature, ceramic surface performed super hydrophilic which might due to thelarge surface porosity. When the sintering temperature reaches a certain extent, ceramicsurface porosity decreases sharply, ceramic surface water contact angle ramained unchangedas the contact time growth. Hydrophilic impurity phase composition might generated whenthe sintering temperature near the melting temperature.During the polarization process of the ceramics, temperature was found to be mostsensitive influence. The polarization under a moderate temperature such as50°C and thepolarization electric field control right such as2.5kV/mm, the potassium sodium niobateceramics internal electric dipole polarization degree of deflection and controllable operationof ceramic piezoelectric constant could realized via controlling the polarization time.In surface potential testing of piezoelectric ceramic, it was found that two sidesrespectively present different potential properties after the potassium sodium niobate ceramics were polarized. The remainder polarization effect of the electric dipole could accumulate onceramic surface, with the potassium sodium niobate piezoelectric polarization degreeincreases, the piezoelectric constant increased and positive and negative surface potential ofcorrespoding surface increased respectively, the more significant difference of the two sidesshowed.In the process of piezoelectric ceramic biomimetic mineralization research, it was foundthat potassium sodium niobate ceramics surface of the negative potential influencesignificantly on the mineralization of calcium phosphate salt deposition. Biomimeticmineralization of calcium phosphate salt membrane layer can be formed on ceramic surface ofnegative potential in a short period of time. However, positive potential surface is notconducive to calcium phosphate salt deposit, there was only NaCl deposited on the surface ofpositive potential.In the research of protein adsorption on potassium sodium niobate piezoelectric ceramic,it was found that BSA protein adsorption amount both on the surface of positive and negativepotential were larger than unpolarized ceramic surface. The adsorption mechanism may bedue to driving force of ceramic surface potential, and the protein molecule structure of bothpositive and negative charged apparent groups. There was no significant cytotoxicity in thepotassium sodium niobate ceramics that prepared via different sintering temperature, whichshowed that the potassium sodium niobate ceramic is biological safe.This paper uses the advanced kelvin probe force microscopic characterized the surface ofthe piezoelectric ceramic after polarization, indicated the relationship between electrostaticpotential and piezoelectric constant directly. Compared with the commonly used thermalstimulation depolarization current method to represent the electrical activity of ceramics afterpolarization, the surface potential reflect more realistic reaction conditions in vivoexperimental environment. And ceramic preparation process is directly related tocontrollability of the piezoelectric constant and the biomedical performance. In this paper, theresearch content and results have important reference meaning to the later research of theinterface reaction betweenpotassium sodium niobate piezoelectric bioceramic and thebiological organism, organization, and biological molecules... |
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