| Budget Amount *help |
¥15,500,000 (Direct Cost: ¥14,600,000、Indirect Cost: ¥900,000)
Fiscal Year 2007: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2006: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2005: ¥6,400,000 (Direct Cost: ¥6,400,000)
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| Research Abstract |
The bio compatibility of metallic biomaterials are characterized electrochemically using conventional polarization measurements under cell culturing condition, a rapid straining electrode technique. The surface modification of metallic materials including stainless steels, Ni-Ti alloy, Ti and its alloys with oxide formation and also electroconductive polymers.
The electrochemical corrosion behavior of Type 304 and 316L stainless steels was studied in Hanks' solution, Eagle's Minimum Essential Medium (MEM), serum containing medium (MEM with 10% of fetal bovine serum) without cells, and serum containing medium with cells over a one-week period. Polarization resistance measurements indicated that the stainless steels were resistant to Hanks' and MEM solutions. Type 304 was more inferior to pitting corrosion than Type 316L in Hanks' and MEM solutions. The uniform corrosion resistance of stainless steels, determined by R_p, was lower in culturing medium than in Hanks' and MEM. The low corros
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ion resistance was due to surface passive film with less protective to reveal high anodic dissolution rate. When cells were present, the initial corrosion resistance was low; but gradually increased after three days, consistent with the trend of cell coverage. The presence of cell was found to suppress the cathodic reaction, that is, oxygen reduction, and increase the uniform corrosion resistance as a consequence. On the other hand, both Type 304 and 316L stainless steels become more susceptible to pitting corrosion when they were covered with cells.
Ti and Ti based alloys are characterized by a continuous electrochemical monitoring and a rapid straining electrode technique in simulated body fluid environment. Materials examined are Ti, Ti-6AI-7Nb, Ti-6AI-4V and Ti-29Nb-13Ta-4.6Zr. Sterilized specimens were immersed in Hanks solution or Eagle's minimum essential medium (MEM) solution. Electrode potential and polarization resistance were simultaneously and continuously measured up to 7 days. For all the specimens examined, the corrosion potential reached to a steady state in 2 days for both solutions. On the other hand, corrosion resistance increased monotonously for the period examined. Less
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