State Key Laboratory of Bioelectronics, School of Chemistry and Chemical Engineering, Jiangning District, Southeast University, Nanjing, 211189, People's Republic of China.
Anal Chem. 2011 Sep 1;83(17):6800-9. doi: 10.1021/ac201558w. Epub 2011 Aug 15.
A signal amplification strategy for sensitive detection of tumor necrosis factor-alpha (TNF-α) using quantum dots (QDs)-polymer-functionalized silica nanosphere as the label was proposed. In this approach, silica nanospheres with good monodispersity and uniform structure were employed as carriers for surface-initiated atom transfer radical polymerization of glycidyl methacrylate, which is readily available functional monomer that possessing easily transformable epoxy groups for subsequent CdTe QDs binding through ring-open reaction. Then, human anti rabbit TNF-α antibody (anti-TNF-α, Ab2, served as a model protein) was bonded to CdTe QDs-modified silica nanospheres coated with polymer to obtain QDs-polymer-functionalized silica nanosphere labels (Si/PGMA/QD/Ab2). The Si/PGMA/QD/Ab2 labels were attached onto a gold electrode surface through a subsequent "sandwich" immunoreaction. This reaction was confirmed by scanning electron microscopy (SEM) and fluorescence microscopic images. Enhanced sensitivity could be achieved by an increase of CdTe QD loading per immunoassay event, because of a large number of surface functional epoxy groups offered by the PGMA. As a result, the electrochemiluminescence (ECL) and square-wave voltammetry (SWV) measurements showed 10.0- and 5.5-fold increases in detection signals, respectively, in comparison with the unamplified method. The detection limits of 7.0 pg mL(-1) and 3.0 pg mL(-1) for TNF-α antibodies by ECL and SWV measurements, respectively, were achieved. The proposed strategy successfully demonstrated a simple, reproducible, specific, and potent method that can be expanded to detect other proteins and DNA.
提出了一种使用量子点（QD）-聚合物功能化硅纳米球作为标记物进行肿瘤坏死因子-α（TNF-α）灵敏检测的信号放大策略。在这种方法中，采用具有良好单分散性和均匀结构的硅纳米球作为引发原子转移自由基聚合的载体，使用易于转化的环氧基功能单体甲基丙烯酸缩水甘油酯，通过开环反应可以很容易地与 CdTe QD 结合。然后，将人抗兔 TNF-α抗体（Ab2，用作模型蛋白）键合到涂有聚合物的 CdTe QD 修饰的硅纳米球上，得到 QD-聚合物功能化硅纳米球标记物（Si/PGMA/QD/Ab2）。通过随后的“三明治”免疫反应，将 Si/PGMA/QD/Ab2 标记物附着到金电极表面。通过扫描电子显微镜（SEM）和荧光显微镜图像证实了这种反应。通过增加免疫分析事件中每个 CdTe QD 的负载量，可以实现增强的灵敏度，这是由于 PGMA 提供了大量的表面功能环氧基。结果，电化学发光（ECL）和方波伏安法（SWV）测量分别显示检测信号增加了 10.0 倍和 5.5 倍，与未放大方法相比。通过 ECL 和 SWV 测量，TNF-α 抗体的检测限分别达到了 7.0 pg mL(-1)和 3.0 pg mL(-1)。该策略成功地证明了一种简单、可重复、特异且有效的方法，可以扩展用于检测其他蛋白质和 DNA。
