Nakahira A, Tamai M, Aritani H, Nakamura S, Yamashita K
Kyoto Institute of Technology, Matsugasaki-Sakyo-ku, Kyoto 606-8585, Japan.
J Biomed Mater Res. 2002 Dec 15;62(4):550-7. doi: 10.1002/jbm.10344.
In the present study, the preparation of dense hydroxyapatite (HAp) materials at relative low temperatures using a spark plasma sintering was carried out. The bioactivity of HAp samples prepared by a spark plasma sintering method was investigated by in vitro tests and compared with HAp obtained by a conventional hot-pressing method. No growth of bone-like HAp crystals on surface of HAp sintered by a conventional hot-pressing method at 1200 degrees C was observed after immersion in a simulated body fluid (SBF) for 2 days. However, many large bone-like HAp crystals were observed on the surface of HAp samples prepared by a spark plasma sintering at 1200 degrees C after 2 days in the SBF immersion test. Especially, the negatively charged surface of the HAp samples prepared by spark plasma sintering was covered with larger HAp crystals compared with the positively charged surface. The electric poling of HAp was measured using a thermally simulated current technique. This rapid growth of bone-like HAp crystals of the HAp samples made by spark plasma sintering was believed to be related with the OH(-) and/or Ca(2(+) ) ion deficiency at the grain boundaries of the HAp matrix grains as well as a small electric poling effect resulting during the spark plasma sintering process.
在本研究中,采用放电等离子烧结法在相对较低温度下制备了致密的羟基磷灰石(HAp)材料。通过体外试验研究了采用放电等离子烧结法制备的HAp样品的生物活性,并与通过传统热压法获得的HAp进行了比较。将在1200℃下通过传统热压法烧结的HAp浸入模拟体液(SBF)中2天后,未观察到其表面有类骨HAp晶体生长。然而,在SBF浸泡试验2天后,在1200℃下通过放电等离子烧结制备的HAp样品表面观察到许多大的类骨HAp晶体。特别是,与带正电的表面相比,通过放电等离子烧结制备的HAp样品带负电的表面覆盖有更大的HAp晶体。采用热模拟电流技术测量了HAp的电极化。认为通过放电等离子烧结制备的HAp样品中类骨HAp晶体的这种快速生长与HAp基体晶粒晶界处的OH(-)和/或Ca(2+)离子缺乏以及放电等离子烧结过程中产生的小电极化效应有关。