双信号细胞电化学法检测氯酚类的毒性

以多壁碳纳米管和离子液体复合修饰电极(MWCNTs-IL/GCE)为工作电极,运用线性扫描伏安法(LSV)研究了人乳腺癌(MCF-7)细胞的电化学行为,检测到了2个明显的氧化峰,其氧化峰电位分别为0.725 V和1.038 V.结合4种嘌呤碱基与模型细胞的电化学行为比较与高效液相色谱分析,确定细胞的电化学响应来源分别为细胞质中黄嘌呤与鸟嘌呤、次黄嘌呤与腺嘌呤的电化学氧化.基于2个响应信号峰电流的变化,研究了五氯酚(PCP)、2,4,6-三氯酚(TCP)和2,4-二氯酚(DCP)对MCF-7细胞的毒性效应,根据剂量-效应关系曲线计算半数抑制效应浓度(IC50)值,并与四甲基偶氮唑盐(MTT)比色法进行比较.结果发现,氯酚类污染物对MCF-7细胞活性有明显抑制作用,细胞电化学法与MTT法测得细胞毒性顺序均为:PCPTCPDCP,表明细胞电化学法可以快速、准确地评价氯酚类污染物的细胞毒性.该研究结果可从核苷酸代谢角度为危害化学品的安全无标记、准确客观的毒性评价方法建立提供新思路.

Assessment of cytotoxicity of chlorophenols using two-signal cell electrochemical method

The linear sweep voltammetric (LSV) behavior of human cervical carcinoma (MCF-7) cells on the multiwall carbon nanotubes and ionic liquid modified glass electrode (MWCNTs-IL/GCE) was studied, and two oxidation peak signals were detected at 0.725 V and 1.038 V. Compared the electrochemical behaviors of four purines with model cell and the high-performance liquid chromatography analysis, the resulting response sources of the voltammetric behaviors were confirmed from the oxidation of xanthine and guanine as well as hypoxanthine and adenine in the cytoplasm of MCF-7 cells. Based on the peak current variation of the two response signals, the cytotoxicitites of pentachlorophenol (PCP), 2,4,6-trichlorophenol (TCP) and 2,4-dichlorophenol (DCP) on MCF-7 cells were assessed. In addition, the 50% inhibitory concentrations (IC₅₀s) were calculated according to the dose-effect relationship curves. The IC₅₀s were further compared with those obtained from the methyl tetrazolium (MTT) assay. The results implied that the chlorophenols could significantly inhibit the viability of MCF-7 cell, and both the toxicity orders obtained from the cell electrochemical detection method and the MTT assay were PCP > TCP > DCP. The cell electrochemical detection method was rapid and accurate in the cytotoxicity assessment of chlorophenols. The research results are expected to provide a new idea for the establishment of safe, label-free, exact and objective toxicity assessment to hazardous chemicals.