Abstract:

Objective    To study the effect of a new titanium-copper alloy on the ultrastructure and genomic DNA of Porphyromonas gingivalis（P.g）. Methods    The titanium-copper alloy with copper content of 2%，5% and 10% were prepared and named Ti-2%Cu，Ti-5%Cu and Ti-10%Cu，respectively. The commercial pure titanium was used as the control，named cp-Ti. P.g were cultured on the surface of these materials and placed on the cell culture plate. The transmission electron microscope was used to scan the ultrastructure，and agarose gel electrophoresis was used to test the genomic DNA of P.g. Results    （1）Under transmission electron microscope：the number of damaged P.g increased with the increase of copper content；the cytomembrane，cytoderm and cytoplasma of P.g in cp-Ti group were intact；the cytoderm and cytomembrane of P.g in Ti-2%Cu，Ti-5%Cu and Ti-10 %Cu were intact，blured and ruptured，and black precipitate and vacuole appeared in the cytoplasma.（2）The agarose gel electrophoresis showed：there was no difference in the amount of genomic DNA in control or experimental groups after being contacted by new titanium-copper alloy of P.g for 24h. Conclusion    Cupper ions in new titanium-copper alloy can damage the ultrastructure of P.g，but cann′t degrade the genomic DNA of it in short time.

Key words: titanium-copper alloy, antibacterial mechanism, Porphyromonas gingivalis, transmission electron microscope, agarose gel electrophoresis

摘要：

目的    研究新型钛铜合金对牙龈卟啉单胞菌超微结构和基因组DNA的影响。方法    制备含铜量质量分数依次为2%、5%和10%的钛铜合金样片作为实验组，分别命名为Ti-2%Cu组、Ti-5%Cu组和Ti-10%Cu组；以商业纯钛样片作为对照组，命名为cp-Ti组。牙龈卟啉单胞菌（Porphyromonas gingivalis，P.g）菌悬液接种于置有各组样片的6孔细胞培养板中培养24 h。透射电镜观察各组样片作用后P.g超微结构的变化；应用琼脂糖凝胶电泳观察细菌基因组DNA的变化。结果    （1）透射电镜结果显示：随着含铜量的增加，菌体结构破坏的细菌数随之增多；且Ti-2%Cu组、Ti-5%Cu组和Ti-10%Cu组的P.g均出现细胞壁破裂，细胞膜模糊不清、内陷、断裂，细胞质外溢出现空泡，细胞内出现黑色沉淀物；而cp-Ti组的细菌未出现明显的菌体超微结构改变，细胞壁和菌毛、细胞膜和细胞质结构清晰。（2）琼脂糖凝胶电泳结果显示：对照组与实验组的P.g经钛铜合金作用24 h后相比较，基因组DNA含量没有明显差别。结论    铜离子可引起P.g超微结构的变化，但短时间内不造成细菌基因组DNA的降解。

关键词: 钛铜合金, 抗菌机制, 牙龈卟啉单胞菌, 透射电镜, 琼脂糖凝胶电泳