功能化石墨烯/聚（3,4-乙撑二氧噻吩）衍生物复合材料的可控制备及其电化学免疫传感研究

Tumor markers (TMs) have been of vital importance in cancer diagnosis and treatment. However, the sensitivity of TMs for early diagnosis is low and can not be widely used. In recent years, graphene (GR) based materials have been widely used in biomedical field. In the project, by a facile one-step electrodeposition method, GR/poly(3,4-ethylenedioxythiophene) derivative (GR/PEDOT derivative) composite films are synthesized on the surface of electrode using graphene oxide (GO) and 3,4-ethylenedioxythiophene (EDOT) derivative in monomer as the starting materials. The obtained GR/PEDOT derivative composite films show large specific area, high conductivity, good biocompatibility and fast redox properties. The formation mechanism, preparation conditions and electrochemical properties of GR/PEDOT derivative are carefully discussed. An efficient method (host-guest chemistry) is used to immobilize bioactive primary antibodies (Ab1) onto the suaface of GR/PEDOT-cyclodextrin composite films. Immunoassay is carried out on a modified electrode using a sandwich assay approach, where Ab1 is covalently bound to the sensing interface to be allowed to capture TM specifically. Afterwards, HRP-Ab2-GO is allowed to bind selectively to the captured TM. Sensitivity is greatly enhanced by an amplified electrocatalytic response by the reduction of enzymatically oxidized thionine in the presence of hydrogen peroxide. The signal enhancement strategie enables high sensitivity and low detection limit for the detection of TM. Moreover, the immunosensor could be used for the detection of multiple TMs in real human serum specimens. The smooth implementation of the project will provide a new platform for the early diagnostics of cancer, which has important theoretical significance and a potential value for practical application.

肿瘤标志物（TM）在癌症临床诊疗中具有重要作用，但目前TM因对早期诊断的敏感性低而难以广泛应用。近年来，石墨烯（GR）基材料在生物医学领域已得到广泛应用。本项目以氧化石墨烯（GO）和3,4－乙撑二氧噻吩衍生物（EDOT衍生物）为原料，通过一步电化学沉积方法制备功能化GR /聚（3,4-乙撑二氧噻吩）衍生物（GR/PEDOT衍生物）复合材料，对复合材料的制备条件、形成原理及电化学性质进行系统研究，发展厚度可控、生物兼容性好、有利于电子传递的纳米传感界面。在此界面上结合主－客体化学作用，将金刚烷标记的肿瘤抗体固定到GR/PEDOT-环糊精传感界面。通过夹心免疫反应结合TM以及肿瘤抗体-HRP-GO复合物，借助纳米材料信号放大技术，实现对TM的高灵敏检测，并推广于复杂生理样品中多种TMs的同时检测。该项目研究成果有望为肿瘤的早期诊断提供新的检测平台，因而具有广泛的生物医学理论依据和临床实用价值。

电化学传感器由于其灵敏度高、稳定性好、操作简便、成本低、在复杂环境中能进行在线监测等特点，在临床医学、药物分析、环境保护等领域得到了广泛的应用。然而，生物体系的复杂性、不稳定性要求科研工作者们设计并建立稳定性更好、灵敏度更高、选择性更专一的生物传感器。基于纳米材料所具有的比表面积大、催化活性高、吸附能力强、生物相容性好等诸多优点，针对生物传感器构建的关键环节即生物传感界面的构建和信号放大策略，本项目引入和制备了一系列不同形貌和结构的纳米材料，包括氧化石墨烯（GO）、石墨烯（GR）、聚（3,4-乙撑二氧噻吩）（PEDOT）以及PEDOT/GO、PEDOT/GR复合材料，并将这些纳米材料用于传感界面的构建，起到信号放大作用，以提高传感器的灵敏度和稳定性。结合生物和纳米组装技术，建立了基于抗原-抗体的免疫传感体系及构建了新型纳米修饰电极体系，实现了对肿瘤标志物、生物小分子及药物小分子的高灵敏检测，为解决疾病诊断、药物检测等相关重要问题提供了理论基础和技术支持。（1）基于抗原-抗体的免疫传感体系研究。a）基于AuNPs/PEDOT/GR和AuNPs/PEDOT/MWCNTs复合材料为固定界面的电化学免疫传感器的制备及其对癌胚抗原（CEA）和甲胎蛋白（AFP）的检测。b）合成了AuNPs/PEDOT/普鲁士蓝（PEDOT/PB）复合材料作为传感界面，构建了电化学免疫传感器用于CEA的检测。c）设计了AuNPs/GR-NB和AuNPs/GR-MWCNTs两种复合传感界面，用于固定CEA抗体和AFP抗体，构建了电化学免疫传感器分别用于CEA和AFP的检测。（2）新型纳米修饰电极体系。通过制备多种功能性GR基纳米复合材料、PEDOT基多种能复合材料修饰电极，结合电化学传感技术，开发新型生物传感器用于生物小分子、药物小分子及重金属离子的检测。