The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, California, USA.
J Biomed Mater Res B Appl Biomater. 2012 Nov;100(8):2279-87. doi: 10.1002/jbm.b.32799. Epub 2012 Sep 15.
The time-dependent degradation of titanium bioactivity (i.e., the biological aging of titanium) has been reported in previous studies. This phenomenon is caused by the loss of hydrophilicity and the inevitable occurrence of progressive contamination of titanium surfaces by hydrocarbons. In this study, we tested the hypothesis that gamma ray treatment, owing to its high energy to decompose and remove organic contaminants, enhances the bioactivity and osteoconductivity of titanium. Titanium disks were acid-etched and stored for 4 weeks. Rat bone marrow-derived osteoblasts (BMOs) were cultured on titanium disks with or without gamma ray treatment (30 kGy) immediately before experiments. The cell density at day 2 increased by 50% on gamma-treated surfaces, which reflected the 25% higher rate of cell proliferation. Osteoblasts on gamma-treated surfaces showed 30% higher alkaline phosphatase activity at day 5 and 60% higher calcium deposition at day 20. The strength of in vivo bone-implant integration increased by 40% at the early healing stage of week 2 for gamma-treated implants. Gamma ray-treated surfaces regained hydrophilicity and showed a lower percentage of carbon (35%) as opposed to 48% on untreated aged surfaces. The data indicated that gamma ray pretreatment of titanium substantially enhances its bioactivity and osteoconductivity, in association with the significant reduction in surface carbon and the recovery of hydrophilicity. The results suggest that gamma ray treatment could be an effective surface enhancement technology to overcome biological aging of titanium and improve the biological properties of titanium implants.
已有研究报道，钛的生物活性（即钛的生物老化）会随时间而降解。这种现象是由于亲水性丧失以及钛表面不可避免地逐渐被碳氢化合物污染所导致的。在本研究中，我们验证了一个假设，即伽马射线处理因其高能量可分解并去除有机污染物，从而增强钛的生物活性和骨诱导性。钛盘经酸蚀处理并储存 4 周。在实验前，将大鼠骨髓源性成骨细胞（BMOs）立即种植在未经伽马射线处理（30 kGy）和经伽马射线处理（30 kGy）的钛盘上。第 2 天，经伽马射线处理表面的细胞密度增加了 50%，这反映了细胞增殖率提高了 25%。第 5 天和第 6 天，经伽马射线处理表面的成骨细胞碱性磷酸酶活性分别提高了 30%和 60%，第 20 天的钙沉积量也提高了 60%。在第 2 周的早期愈合阶段，经伽马射线处理的植入物的体内骨-植入物整合强度提高了 40%。经伽马射线处理的表面恢复了亲水性，且其表面的碳含量（35%）明显低于未经处理的老化表面（48%）。这些数据表明，伽马射线预处理可显著增强钛的生物活性和骨诱导性，同时显著降低表面碳含量并恢复亲水性。结果表明，伽马射线处理可能是一种有效的表面增强技术，可克服钛的生物老化，提高钛植入物的生物学性能。
