基于无酶循环放大策略的多通道纳米电化学生物传感器用于肝癌多元肿瘤标志物的联合检测

Liver cancer is one of the common malignant tumors in China, with the morbidity rising year by year. A significant proportion of liver cancers initially are asymptomatic lesions and are not diagnosed or treated until they reach an intermediate or advanced stage. Therefore, the early diagnosis of liver cancer is the most effective means to reduce mortality rate from this disease. So far, the commonly used early diagnosis are imageology and hepatic tissue biopsy in clinic. However, these methods have some disadvantages including lower sensitivity, higher assay costs, relatively long assay times, more complicated operation, and invasion. Thus, it is very important to develop a kind of sensitive, accurate, convenient, fast, economic, non-invasive method for the increase of accurate rate and the implementation of nationwide large scale screening. In this research project, we will develop a multichannel nano-electrochemical biosensor based on enzyme-free recycling. By employed this sensor, the combined detection for three kinds of tumor markers such as DNA, microRNA and growth factor will be realized. By comparing the levels of tumor markers between liver cancer group, benign liver disease group and healthy control group, we can establish a new method for early diagnosis of liver cancer. Compared with the current used methods based on single tumor marker alpha-fetoprotein detection, or the protein biochip for combined detection of antigen，enzyme，proteins and et al, the sensor can detect multielement liver tumor markers simultaneously, which make the accuracy of liver cancer early diagnosis increase greatly.

我国是肝癌的重灾区，发病率呈逐年上升趋势。因初期症状不明显，肝癌确诊时已多属中、晚期，缺乏有效治疗。因此，肝癌早期诊断极为重要。然而目前临床上常用的影像学检查和肝组织活检等方法或灵敏度低、昂贵、耗时，或操作复杂、创伤性大。因此，研究一种灵敏、准确、简便、快速、经济、非创伤性的检测新技术，对提高肝癌早期诊断的准确率和开展全国范围内尤其是经济欠发达地区的肝癌普查，具有极其重要的意义。因此，本项目拟研制一种基于"无酶循环信号放大策略"的多通道纳米电化学生物传感器，并将其用于DNA、microRNA和生长因子三种不同类型肝癌标志物的联合检测。通过对比肝癌组、良性肝病组与健康对照组血液中标志物的水平，建立肝癌早期诊断的新方法。与目前临床上使用的基于甲胎蛋白单一肿瘤标志物的检测技术，或基于抗原、酶、蛋白质等联合检测的蛋白芯片技术相比，该传感器可联合检测多元肿瘤标志物，大大提高了肝癌早期诊断的准确率。

提高肝癌患者存活率的重要原则是早诊断、早发现、早治疗，其中最关键的是早期诊断。肿瘤标志物检测是诊断肝癌的重要手段。然而，仅通过一种标志物的检测结果诊断肝癌时，敏感性和特异性均较低，特别是对肝癌早期患者更容易漏检和误诊，难以满足临床实际的需要。为弥补单一检测的不足，课题组提出构建新型的电化学生物传感器，同时检测肝癌相关特异性表达基因MXR7基因、microRNA-122和血管内皮生长因子（VEGF）来诊断肝癌。经过3年努力，课题组设计了适合的探针做为靶分子识别元件，引入“无酶循环信号放大策略”、“酶辅助目标序列循环”、“DNAzyme模拟酶”、“磁性可控电极”、“DNA长距自组装”等技术，有效的提高了DNA电化学传感器的灵敏度和选择性。此外，课题组还将研制的传感器用于临床实际样本的检测，希望能通过对比肝癌患者与正常对照组样本中的相关标志物水平，评价传感器在临床检测中的实际应用价值，为研制超灵敏非标记型电化学生物传感器并最终应用于肝癌早期诊断和预后监测提供研究基础。课题组认为伴随着电子技术的不断发展，这种便携式电化学检测设备由于不需要固定场所、不依赖专业人员，在实际应用中可对依赖大型仪器的检测方法形成补充，实现即时检验的目的，从而有效提高我国现有医疗体系的健康保障水平。