NanoScience Technology Center, University of Central Florida, Orlando, Florida 32826, USA.
Analyst. 2013 Oct 7;138(19):5713-8. doi: 10.1039/c3an00967j.
Under physiological and wear conditions, implanted orthopedic devices undergo undesired release of metal ions which cause DNA damage and inflammation of local tissue. However, individuals have personalized responses to identical devices due to varying susceptibility to DNA damage. The current one-size-fits-all approach is therefore not suitable to predict the response of patients to implanted devices. This paper describes a single cell array based method to quantify metal ion induced DNA damage that can potentially be used to predict the response to implanted devices in patients. Ions of several typical metals in implanted devices were used to treat human normal fibroblast cells. After patterning cells on a silicon substrate with cell-catching patches, cells were embedded in hydrogel and treated with alkaline buffer. Damaged DNAs diffuse out of the cell, and are stained to show a characteristic halo. All studied metal ions (Cu(2+), Co(2+), Ni(2+), Cr(2+), Fe(2+), Al(3+)) induce DNA damage and have genotoxicity. Copper ions cause DNA damage at concentrations as low as 1 μM. Cobalt and nickel ions damage DNA at 5 and 10 μM, respectively. Aluminum, iron and chromium ions cause DNA damage at 50 μM. The cytotoxicity assay shows that most ions, except cobalt and copper, are less toxic below 500 μM. The fact that metal ions can cause genotoxicity at lower concentrations than that of cytotoxicity suggests: (1) a single cell based DNA damage assay is more sensitive than a membrane integrity based live/dead assay; and (2) metal ions preferentially induce DNA damage rather than cell membrane damage.
在生理和磨损条件下，植入的骨科设备会释放出有害的金属离子，这些离子会导致 DNA 损伤和局部组织炎症。然而，由于对 DNA 损伤的敏感性不同，个体对相同的设备会产生个性化的反应。因此，目前一刀切的方法并不适合预测患者对植入设备的反应。本文描述了一种基于单细胞阵列的方法，可定量测量金属离子诱导的 DNA 损伤，该方法可能用于预测患者对植入设备的反应。我们使用植入设备中几种典型金属的离子来处理人正常成纤维细胞。在硅衬底上用细胞捕获斑图案化细胞后，将细胞嵌入水凝胶中并用碱性缓冲液处理。受损的 DNA 从细胞中扩散出来，并被染色以显示出特征性的晕圈。所有研究的金属离子（Cu(2+)、Co(2+)、Ni(2+)、Cr(2+)、Fe(2+)、Al(3+)）都能诱导 DNA 损伤并具有遗传毒性。铜离子在低至 1 μM 的浓度下就能引起 DNA 损伤。钴离子和镍离子分别在 5 和 10 μM 时损伤 DNA。铝、铁和铬离子在 50 μM 时引起 DNA 损伤。细胞毒性测定表明，除钴和铜外，大多数离子在低于 500 μM 时毒性较低。金属离子在低于细胞毒性的浓度下就能引起遗传毒性的事实表明：（1）基于单细胞的 DNA 损伤测定比基于膜完整性的死活测定更灵敏；（2）金属离子优先诱导 DNA 损伤而不是细胞膜损伤。
