中文摘要：

采用Fe3O4／ZrO2（壳）纳米磁珠（zMPs）标记待测物识别抗体，并用HRP酶封闭和DNA链接，建立了一类新型的“珠链状”一维磁性纳米探针制备方法。将甲胎蛋白（AFP）一抗固定于纳米金修饰的玻碳电极表面，构建了免疫电极（GCElAFPAb。）。基于该电极和上述合成探针，通过双抗体夹心法测定免疫产物上HRP酶对过氧化脲（CP）氧化对苯二酚反应的催化电流，研制了一类基于一维纳米结构组装的夹心型安培免疫传感器。研究表明：此一维纳米结构探针不仅大大增加了酶在电极表面的富集量，成倍扩增了催化电流，显著提高了传感器的灵敏度，而且易于通过外磁场与背景液可控分离，简化了分析步骤，并提高了结果的重复性。此传感器对AFP检测的线性范围为0．01～25μg／L；检出限达4ng／L（3σ），并被用于人血清中痕量AFP的测定，结果满意。

英文摘要：

A new type of one-dimensional magnetic nanoprobes was fabricated based on a DNA chain fixed with a number of Fe3O4 （core）/ZrO2 （shell） nano-magnetic beads （ZMPs） labeled with secondary antibody. The α-fetoprotein （AFP） was analyzed by using probes DNA/（ZMPs-HRP-AFP Ab2）n and immobilizing α-fetoprotein antibody （AFP Abl ） onto the glassy carbon electrode modified by nano-gold. The sandwich-type immunocomplex could be formed between the immobilized AFP Abl on the GCE and the probes DNA/（ZMPs-HRP-AFP Ab2） n and the carried HRP could catalyze the electrochemical reduction of carbamide peroxide （CP） with the help of hydroquinone （HQ）. The novel one-dimensional nano structure assemble and sandwich-type amperometric immunosensor was developed. Enhanced sensitivity was achieved by introducing more HRP-AFP Ab2 onto the electrode surface through the pearl chain structure. Under optimal conditions, the proposed method could respond to 4 ng/L AFP with a linear calibration range from 0.01 to 25 μg/L. The immunosensor was employed to determine AFP in serum samples and the results were satisfactory. The proposed amperometric immunosensor was sensitive, quick, magnetic field controllable. This study provided a platform technology for developing a one-dimensional assembly and highly sensitive immunosensor, which was suitable for screen determination of tumors in serums of normal patients.