Tang Dianping, Yuan Ruo, Chai Yaqin
Key Laboratory of Analytical Chemistry (Chongqing), College of Chemistry and Chemical Engineering, Southwest University, Chongqing, People's Republic of China.
Clin Chem. 2007 Jul;53(7):1323-9. doi: 10.1373/clinchem.2006.085126. Epub 2007 May 17.
Methods based on magnetic bead probes have been developed for immunoassay, but most involve complicated labeling or stripping procedures and are unsuitable for routine use.
We synthesized magnet core/shell NiFe(2)O(4)/SiO(2) nanoparticles and fabricated an electrochemical magnetic controlled microfluidic device for the detection of 4 tumor markers. The immunoassay system consisted of 5 working electrodes and an Ag/AgCl reference electrode integrated on a glass substrate. Each working electrode contained a different antibody immobilized on the NiFe(2)O(4)/SiO(2) nanoparticle surface and was capable of measuring a specific tumor marker using noncompetitive electrochemical immunoassay.
Under optimal conditions, the multiplex immunoassay enabled the simultaneous detection of 4 tumor markers. The sensor detection limit was <0.5 microg/L (or <0.5 kunits/L) for most analytes. Intra- and interassay imprecisions (CVs) were <4.5% and 8.7% for analyte concentrations >5 mug/L (or >5 kunits/L), respectively. No nonspecific adsorption was observed during a series of procedures to detect target proteins, and electrochemical cross-talk (CV) between neighboring sites was <10%.
This immunoassay system offers promise for label-free, rapid, simple, cost-effective analysis of biological samples. Importantly, the chip-based immunosensor could be suitable for use in the mass production of miniaturized lab-on-a-chip devices and open new opportunities for protein diagnostics and biosecurity.
基于磁珠探针的方法已被开发用于免疫分析，但大多数方法涉及复杂的标记或剥离程序，不适合常规使用。
我们合成了磁芯/壳层NiFe(2)O(4)/SiO(2)纳米颗粒，并制造了一种用于检测4种肿瘤标志物的电化学磁控微流控装置。免疫分析系统由集成在玻璃基板上的5个工作电极和一个Ag/AgCl参比电极组成。每个工作电极包含固定在NiFe(2)O(4)/SiO(2)纳米颗粒表面的不同抗体，并且能够使用非竞争性电化学免疫分析法测量特定的肿瘤标志物。
在最佳条件下，多重免疫分析能够同时检测4种肿瘤标志物。对于大多数分析物，传感器检测限<0.5μg/L（或<0.5k单位/L）。当分析物浓度>5μg/L（或>5k单位/L）时，批内和批间不精密度（CV）分别<4.5%和8.7%。在检测目标蛋白的一系列程序中未观察到非特异性吸附，相邻位点之间的电化学串扰（CV）<10%。
这种免疫分析系统为生物样品的无标记、快速、简单、经济高效的分析提供了前景。重要的是，基于芯片的免疫传感器可能适用于大规模生产小型化的芯片实验室设备，并为蛋白质诊断和生物安全开辟新的机会。
