元素标记DNA分子机器在ICP-MS/OES同时检测多个肿瘤标志物中的新策略研究

肿瘤标志物可用于肿瘤诊断、病情发展及预后效果判断，其定量检测尤其是多个标志物的同时检测对肿瘤早期诊疗从而提高治愈率有极其重要的作用。目前肿瘤标志物的检测主要基于酶联免疫法(ELISA)，但肿瘤样本中对应标志物种类多、含量低且基体复杂，对其准确的同时检测具有很大的困难。本项目拟构建一种集成目标物识别、信号转换与输出分离功能的DNA分子机器，利用磁球作为运行轨道、不同识别配体修饰的DNA作为探针、脱氧核酶作为动力、各类元素标记的核酶底物为信号分子。通过双DNA探针识别目标物，诱导同一脱氧核酶对多个底物依次组装和切割，促使该核酶在轨道表面“移动”，释放大量元素标记的底物，从而实现信号转换和扩增。通过磁分离后，利用ICP-MS/OES的高选择性与高灵敏度，最终达到对多个肿瘤标志物的同时检测目的。该方法将为早期医疗提供一种技术基础，期望能够成为医院对临床肿瘤患者诊疗的有效手段之一。

Tumor biomarkers can be used for cancer diagnosis, epidemiology and prognosis. And its quantitative analysis, especially for simultaneous analysis of multiple cancer biomarkers, is significant important to early cancer theranostics for improvement of cure rate. In general, quantitative determination of cancer biomarkers relies on ELISA. However, the low content, diversity of tumor biomarkers and complicated matrix in real blood sample bring great difficulties to accurately quantitative analysis of cancer biomarkers. By using magnetic beads as moving track, various affinity ligands conjugated DNA as recognition probe, DNAzyme as driven power and different elements-labelled substrates as signal molecules, we here proposed one DNA molecular machine integrated with recognition, signal conversion, signal output and purification. In the presence of target, the two recognition probes binding to same target induce association and cleavage of single DNAzyme with the substrates，initiating the stepwise movement of the DNAzyme along the tracks. Meanwhile, a large number of elements-labelled substrates is releasing from the surface of magnetic beads, realizing signal conversion and amplification. After magnetic purification, simultaneous determination of multiple tumor biomarkers can be achieved by utilizing Inductively Coupled Plasma Mass Spectrometry/ Optical Emission Spectrometry (ICP-MS/OES) with high selectivity and sensitivity. The method will provide a technical basis for early medical care. It is expected that this method will become one of the effective theranostic means for clinical patients.