基于GMR生物传感器的甲胎蛋白检测

采用磁控溅射、光刻、离子束刻蚀和剥离工艺等工艺和方法,制备了多层膜结构的巨磁阻(GMR)生物传感器件,并利用此种传感器来检测甲胎蛋白。在传感器表面通过生物处理固定甲胎蛋白单克隆抗体(McAb1)作为探针,以捕获目标抗原———甲胎蛋白。用直径1μm的超顺磁磁珠标记目标抗原。当传感器表面抗体将目标抗原捕获后,磁珠标记即被固定在GMR传感器的表面。垂直于传感器表面施加230 Oe(1 Am-1=4π×10-3 Oe)的磁场,即可检测到由磁珠产生的信号。本实验对质量浓度为1 ng/mL的甲胎蛋白进行了检测,得到了信号为0.29～0.34Ω的电阻变化值。此种检测方法可用于诊断原发性肝癌。

Assays of Alpha-Fetoprotein Based on the GMR Bio-Sensor

The giant magnetoresistance(GMR) sensor with the multilayer film structure was fabricated with the magnetron sputtering,lithography,ion beam etching,lift-off and other technologies.The GMR sensors were used to assay the alpha-fetoprotein(AFP).Antibody McAb1 fixed on the surface of the sensor was used as the probe to capture the target antigen-AFP,which was marked by the super paramagnetic magnetic beads with the diameter of 1 μm.When the target antigen on the surface of the sensor was captured by the antibody,the magnetic bead mark was fixed on the surface of GMR sensor.The signals caused by the magnetic beads can be detected,when the vertical magnetic field of 230 Oe was applied.In this experiment,the AFP with the mass concentration of 1 ng/mL was detected,which caused the GMR resistance change of 0.29-0.34 Ω.This method can be used for the diagnosis of the primary liver cancer.