Tang Dianping, Yuan Ruo, Chai Yaqin
Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, 400700, Chongqing, PR China.
Biotechnol Lett. 2006 Apr;28(8):559-65. doi: 10.1007/s10529-006-0017-4.
A direct electrochemical immunoassay system based on the immobilization of alpha-1-fetoprotein antibody (anti-AFP), as a model system, on the surface of core-shell Fe(2)O(3)/Au magnetic nanoparticles (MNP) has been demonstrated. To fabricate such an assay system, anti-AFP was initially covalently immobilized on to the surface of core-shell Fe(2)O(3)/Au MNP. Anti-AFP-modified MNP (bio-nanoparticles) were then attached to the surface of carbon paste electrode with the aid of a permanent magnet. The performance and factors influencing the performance of the resulting immunosensor were studied. alpha-1-Fetoprotein antigen was directly determined by the change in current or potential before and after the antigen-antibody reaction versus saturated calomel electrode. The electrochemical immunoassay system reached 95% of steady-state potential within 2 min and had a sensitivity of 25.8 mV. The linear range for AFP determination was from 1 to 80 ng AFP ml(-1) with a detection limit of 0.5 ng AFP ml(-1). Moreover, the direct electrochemical immunoassay system, based on a functional MNP, can be developed further for DNA sensor and enzyme biosensor.
已证明一种基于将甲胎蛋白抗体（抗 AFP）作为模型系统固定在核壳型 Fe(2)O(3)/Au 磁性纳米颗粒（MNP）表面的直接电化学免疫分析系统。为构建这样一种分析系统，首先将抗 AFP 共价固定在核壳型 Fe(2)O(3)/Au MNP 的表面。然后借助永久磁铁将抗 AFP 修饰的 MNP（生物纳米颗粒）附着到碳糊电极表面。研究了所得免疫传感器的性能及影响其性能的因素。通过抗原 - 抗体反应前后相对于饱和甘汞电极的电流或电位变化直接测定甲胎蛋白抗原。该电化学免疫分析系统在 2 分钟内达到稳态电位的 95%，灵敏度为 25.8 mV。AFP 测定的线性范围为 1 至 80 ng AFP ml(-1)，检测限为 0.5 ng AFP ml(-1)。此外，基于功能性 MNP 的直接电化学免疫分析系统可进一步开发用于 DNA 传感器和酶生物传感器。
