磁免疫和荧光免疫传感器的构建及其在检测甲胎蛋白中的应用

Development of Magnetic and Fluorescent Immune Sensors for the Detection of Alpha Fetoprotein

甲胎蛋白(AFP)是常见的肝癌肿瘤标志物,在早期诊断方面起到重要作用。分别设计构建了磁免疫和荧光免疫传感器并将其应用于AFP的定量检测。在磁免疫传感器中,采用免疫磁珠代替传统固相载体,实现了目标物的快速分离;利用标记抗体上的辣根过氧化物酶(HRP)催化底物显色,根据底物吸光度值的大小进行定量检测。构建的AFP检测方法的检出限为3.6ng·mL^(-1),线性范围为10~80ng·mL^(-1)。在荧光免疫传感器中,将碲化镉量子点(CdTe QDs)的荧光作为信号输出,并通过同时将多个CdTe QDs连接在纳米硅球表面实现信号放大,通过测量量子点荧光强度实现定量检测。该方法AFP检出限为4.2ng·mL^(-1),线性范围为5~150ng·mL^(-1)。所设计的两种传感器均具有特异性强、灵敏度高的特点,为AFP的检测提供了新的思路和方法。

Alpha fetoprotein （AFP） is one of the most widely used tumor biomarkers with significant values in early diagnosis of liver cancer. We designed both magnetic and fluorescent immune sensors in this work and utilized them in the detection of AFP in solutions. For the magnetic immune sensor, the immunomagnetic beads were applied to replace the traditional solid support because the immunomagnetic beads had larger specific surface areas which ensured the sufficiency of the antibody-antigen reaction. With the help of magnetic response, the separation process could be achieved rapidly, which was time-saving and nondestructive. Horseradish Peroxidase （HRP） on the Ab2 could catalyze the substrates to chromogenic products which could be tested with UV-Vis spectrophotometry. The method had a correlation in the range of 10~80 ng·mL-1 with a detection limit of 3.6 ng·mL-1. For the fluorescent immune sensor, we considered the fluorescence of CdTe QDs to be the output signal, and at the same time, a signal amplification system was introduced by doping the CdTe QDs onto the surface of the silica nanospheres which were suitable as the carrier for their adjustable size and stable properties. The fluorescent intensity of CdTe QDs was tested to calculate the concentration of AFP. The method reached a detection limit of 4.2 ng·mL-1 with a linear range of 5~150 ng·mL-1. It was shown that both the developed magnetic and fluorescent immune sensors had high sensitivity to detect the concentration of AFP in solutions.